Oreochromis fishes exhibit variability of sex-determination (SD) genes whose characterization con... more Oreochromis fishes exhibit variability of sex-determination (SD) genes whose characterization contributes to understanding of the sex differentiation network, and to effective tilapia farming, which requires all-male culture. However, O. niloticus (On) amh is the only master-key regulator (MKR) of SD that has been mapped (XY/XX SD-system on LG23). In O. aureus (Oa), LG3 controls a WZ/ZZ SD-system that has recently been delimited to 9.2 Mbp, with an embedded interval rich with female-specific variation, harboring two paics genes and banf2. Developing genetic markers within this interval and using a hybrid Oa stock that demonstrates no recombination repression in LG3, we mapped the critical SD region to 235 Kbp on the orthologous On physical map (p < 1.5 × 10−26). DNA-seq assembly and peak-proportion analysis of variation based on Sanger chromatograms allowed the characterization of copy-number variation (CNV) of banf2. Oa males had three exons capable of encoding 90-amino-acid pol...
Various master key regulators (MKRs) that control a binary switch of sex determination (SD) have ... more Various master key regulators (MKRs) that control a binary switch of sex determination (SD) have been found in fish; these provide an excellent model for the study of vertebrate genetic SD. The SD region in flathead grey mullet has been previously mapped to a 1 Mbp region harboring 27 genes, of which one is follicle-stimulating hormone receptor (fshr). Although this gene is involved in gonad differentiation and function, it has not been considered as an MKR of SD. We systematically investigated polymorphism in mullet fshr using DNA shotgun sequences, and compared them between males and females. Capable of encoding nonconservative amino acid substitutions, c.1732G>A and c.1759T>G exhibited association with sex on a population level (N = 83; P ≤ 6.7 × 10−19). Hence, 1732 A and 1759 G represent a male-specific haplotype of the gene, designated as “fshry.” Additional flanking SNPs showed a weaker degree of association with sex, delimiting the SD critical region to 143 nucleotides ...
Differentiation of cells by flow cytometry provides informative somatic cell counts (SCCs) that a... more Differentiation of cells by flow cytometry provides informative somatic cell counts (SCCs) that allow analyzing leukocyte population patterns in udder infections of different etiologies. Postulating that this approach also enhances the statistical power to detect genetic variants linked to cell levels in milk of healthy mammary glands, we used monoclonal antibodies anti-CD18, anti-CD4, anti--CD14, and anti-PMN to count cells presenting these surface antigens, and performed a genome-wide association study of these counts in 125 Israeli Holsteins genotyped using SNP BeadChips. We identified an informative haplotype of 15 SNPs in the centromeric end of BTA3 that was strongly associated with CD18 cells (p < 2.3 × 10−9). Within this region, examination of the network of genes interacting with ITGB2 (CD18) indicated an Fc-γ-receptor gene cluster, including FCGR2A (CD32). Sanger-sequence analysis of FCGR2s-linked exon 3 variation to CD18 counts. Meta-analysis of RNA-Seq data revealed a ...
Background: Crossover localization during meiotic recombination is mediated by the fast-evolving ... more Background: Crossover localization during meiotic recombination is mediated by the fast-evolving zinc-finger (ZnF) domain of gene PRDM9. To study its impact on dairy cattle performance, we compared its genetic variation between the relatively small Israeli (IL) Holsteins and the North American (US) Holsteins that count millions. Results: Initially, we analyzed the major BTA1 haplotypes present in IL Holsteins based on the 10 most telomeric SNPs of the BovineSNP50 BeadChip. Sequencing of representative haplotype carriers indicated that for all frequent haplotypes (> 6%), the variable PRDM9 ZnF array consisted of seven tandem ZnF repeats. Two rare haplotypes (frequency < 4%) carried an indicine PRDM9, whereas all others were variants of the taurine type. These two haplotypes included the minor SNP allele, which was perfectly linked with a previously described PRDM9 allele known to induce unique localization of recombination hotspots. One of them had a significant (p = 0.03) negative effect on IL sire fertility. This haplotype combined the rare minor alleles of the only SNPs with significant (p < 0.05) negative substitution effects on US sire fertility (SCR). Analysis of telomeric SNPs indicated general agreement of allele frequencies (R = 0.95) and of the substitution effects on sire fertility (SCR, R = 0.6) between the US and IL samples. Surprisingly, the alleles that had a negative impact on male fertility had the most positive substitution effects on female fertility traits (DPR, CCR and HCR). Conclusions: A negative genetic correlation between male and female fertility is encoded within the BTA1 telomere. Cloning the taurine PRDM9 gene, which is the common form carried by Holsteins, we encountered the infiltration of an indicine PRDM9 variant into this population. During meiosis, in heterozygous males, the indicine PRDM9 variant may induce incompatibility of recombination hotspots and male infertility. However, this variant is associated with favorable female fertility, which would explain its survival and the general negative correlation (R = − 0.3) observed between male and female fertility in US Holsteins. Further research is needed to explain the mechanism underlying this positive effect and to devise a methodology to unlink it from the negative effect on male fertility during breeding.
Effective farming of tilapia requires all-male culture, characterized by uniformity and high grow... more Effective farming of tilapia requires all-male culture, characterized by uniformity and high growth rate. Males of O. aureus (Oa) and females of O. niloticus (On) produce all-male offspring, but there is a behavioral reproductive barrier between the two species that prevents mass production. In crosses between Oa and On broodstocks, few hybrid females are attracted to the Oa male nests (denoted responders), and if they harbor the On alleles for the sex determination (SD) sites on linkage groups (LGs) 1, 3, and 23, all-male progeny are produced. Yet, without controlling for the alleles underlying SD, the parental stocks gradually lose their capability for all-male production. Hypothesizing that markerassisted selection for female responders would allow production of sustainable broodstocks, we applied genotyping-bysequencing to generate 4983 informative SNPs from 13 responding and 28 non-responding females from two full-sib families. Accounting for multiple comparisons in a genome-wide association study, seven SNPs met a false discovery rate of 0.061. Lowest nominal probabilities were on LGs 9 and 14, for which microsatellite DNA markers were designed within the candidate genes PTGDSL and CASRL, respectively. By increasing the sample size to 22 responders and 47 non-responders and by genotyping additional established microsatellites, we confirmed the association of these LGs with female responsiveness. The combined effects of microsatellites GM171 and CARSL-LOC100690618 on LGs 9 and 14 explained 37% of the phenotypic variance of reproductive interaction (p < 0.0001). Based on these findings, we propose a strategy for mass production of all-male tilapia hybrids through selection for genomic loci affecting SD and female responsiveness.
Background: Sheep production in Israel has improved by crossing the fat-tailed local Awassi breed... more Background: Sheep production in Israel has improved by crossing the fat-tailed local Awassi breed with the East Friesian and later, with the Booroola Merino breed, which led to the formation of the highly prolific Afec-Assaf strain. This strain differs from its parental Awassi breed in morphological traits such as tail and horn size, coat pigmentation and wool characteristics, as well as in production, reproductive and health traits. To identify major genes associated with the formation of the Afec-Assaf strain, we genotyped 41 Awassi and 141 Afec-Assaf sheep using the Illumina Ovine SNP50 BeadChip array, and analyzed the results with PLINK and EMMAX software. The detected variable genomic regions that differed between Awassi and Afec-Assaf sheep (variable genomic regions; VGR) were compared to selection signatures that were reported in 48 published genome-wide association studies in sheep. Because the Afec-Assaf strain, but not the Awassi breed, carries the Booroola mutation, association analysis of BMPR1B used as the test gene was performed to evaluate the ability of this study to identify a VGR that includes such a major gene. Results: Of the 20 detected VGR, 12 were novel to this study. A ~7-Mb VGR was identified on Ovies aries chromosome OAR6 where the Booroola mutation is located. Similar to other studies, the most significant VGR was detected on OAR10, in a region that contains candidate genes affecting horn type (RXFP2), climate adaptation (ALOX5AP), fiber diameter (KATNAl1), coat pigmentation (FRY) and genes associated with fat distribution. The VGR on OAR2 included BNC2, which is also involved in controlling coat pigmentation in sheep. Six other VGR contained genes that were shown to be involved in coat pigmentation by analyzing their mammalian orthologues. Genes associated with fat distribution in humans, including GRB14 and COBLL1, were located in additional VGR. Sequencing DNA from Awassi and Afec-Assaf individuals revealed non-synonymous mutations in some of these candidate genes. Conclusions: Our results highlight VGR that differentiate the Awassi breed from the Afec-Assaf strain, some of which may include genes that confer an advantage to Afec-Assaf and Assaf over Awassi sheep with respect to intensive sheep production under Mediterranean conditions.
Investigative ophthalmology & visual science, Mar 1, 2017
Applying CNGA3 gene augmentation therapy to cure a novel causative mutation underlying achromatop... more Applying CNGA3 gene augmentation therapy to cure a novel causative mutation underlying achromatopsia (ACHM) in sheep. Impaired vision that spontaneously appeared in newborn lambs was characterized by behavioral, electroretinographic (ERG), and histologic techniques. Deep-sequencing reads of an affected lamb and an unaffected lamb were compared within conserved genomic regions orthologous to human genes involved in similar visual impairment. Observed nonsynonymous amino acid substitutions were classified by their deleteriousness score. The putative causative mutation was assessed by producing compound CNGA3 heterozygotes and applying gene augmentation therapy using the orthologous human cDNA. Behavioral assessment revealed day blindness, and subsequent ERG examination showed attenuated photopic responses. Histologic and immunohistochemical examination of affected sheep eyes did not reveal degeneration, and cone photoreceptors expressing CNGA3 were present. Bioinformatics and sequenci...
As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusiv... more As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.
As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusiv... more As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.
Recent studies have revealed that the major genes of the mammalian sex determination pathway are ... more Recent studies have revealed that the major genes of the mammalian sex determination pathway are also involved in sex determination of fish. Several studies have reported QTL In various species and strains of tilapia, regions contributing to sex determination have been identified on linkage groups 1, 3, and 23. Genes contributing to sex-specific mortality have been detected on linkage groups 2, 6 and 23. To test whether the same genes might control sex determination in mammals and fishes, we mapped 11 genes that are considered as putative master key regulators of sex determination: Amh,
segregation of body and peritoneum ptgmentation was studied in three developmental stages in F2 h... more segregation of body and peritoneum ptgmentation was studied in three developmental stages in F2 hybrids and progeny or ri nvoriJr nac[crosseo with parents oreochromis aureus (black body and
Specific antisera against red blood cells of some tilapia species were obtained by reciprocal int... more Specific antisera against red blood cells of some tilapia species were obtained by reciprocal interspecific and intergeneric immunizations. The antisera were used to confirm co-dominant expression of epitopes in F 1 interspecific hybrids and to identify the parental origin of three red tilapia strains. The antisera in all hybrids (Oreochromis niloticus x O. mossambicus, O. aureus x O. hornorum, O. niloticus x S. galilaeus and O. niloticus x O. aureus) were positive to both parental strains. However, while all F 1 hybrids of O. mossambicus x O. hornorum were positive to anti-O. mossambicus antiserum, only 50% were positive to anti-O. hornorum antiserum. In most cases, these results point to co-dominant expression of the species-specific epitopes in hybrids. In addition, the triple parental origins of the Philippine red tilapia (positive for O. aureus, O. mossambicus and O. niloticus epitopes) and of mossambicus red tilapia (positive for O. hornorum, O. mossambicus and O. niloticus epitopes) were assessed. The O. niloticus red tilapia, described as a purebred red variant of O. niloticus, was positive for both anti-O. niloticus and anti-O. aureus antibodies, with a significantly more intense reaction to the latter. A possible genetic basis of this last finding is discussed.
A bimodal distribution in the spontaneous chemiluminescence (SpCL) measurements in naive tilapia ... more A bimodal distribution in the spontaneous chemiluminescence (SpCL) measurements in naive tilapia leads us to divide the fish into low and high responder groups. Because of the homogeneity in both differential phagocyte cell counts and stimulation indexes, it is suggested that diffeiencei between the responder groups are due to innate intrinsic factors. Difference between these two groups is also displayed, in a less significant manner, in zymosan stimulated chemiluminescence (zStCL) that showed a weak linear regression factor (R2=0.4756). ln naive Iilapia, Streptococcus difficile bacterin-stimulated chemiluminescence (bStCL) values were much lowerthan those obtained in zStCL. When sibling fish were infected with live S. difficite bacteria, a spectacular increase in bStCL values, with a high stimulation index of 4.2, was displayed on day 6 after infection. The SpCL and bStCL values increased considerably in diseased fish which displayed a serious symptomatology on day 36 after infection. However, fish that developed resistance to the disease showed lowered values in both SpCL and bStCL. The implication of these f indings in the in vivo production of reactive oxygen radicals by phagocytic cells and their connection to resistance and susceptibility to disease are discussed in comparison to mammals.
Production of viable diploid mitogynogenetic tilapias was achieved using Oreochromis aureus eggs ... more Production of viable diploid mitogynogenetic tilapias was achieved using Oreochromis aureus eggs collected from a third generation of meiogynogenetic females, fertilized with UV-irradiated sperm of red tilapia. Diploidy was restored by cold shock treatment (1 h at 1 1'C) stafting at the zygotic age of 77 min. Mitogynogens could be identif ied at embryo and juvenile ages on the basis of their body pigmentation, which clearly differentiated them from normal hybrid controls which showed the presence of paternally inherited red and yellow chromatophores. Because of asynchronization in cell divisions, assessed during the first, second and third cell division periods, maximal increment cleavage times (MICT) were defined within these periods. Intervals between MICT's define a cell cycle length of exactly 28 min between these cleavages performed a|28.2+0.2'C and of 75 min between the second meiotic and first mitotic divisions. The optimal cleavage blocking time (OCBT), which leads to diploidization when cold shock is applied, could be defined as occurring 2 min before MICT following shocking of embryo groups at different intervals of time before and after MICT. Because MICT is separated by only 2 min from OCBT, it is suggested that furrow appearance, namely the contractile ring formation, is directly influenced by cold shock rather than the spindle chromosome separation mechanism.
Poecilia reticulata is one of the most popular ornamental fish species with a higher demand for m... more Poecilia reticulata is one of the most popular ornamental fish species with a higher demand for males due to their large colorful fins. The objectives of this study were mapping of the sex-determining (SD) region on linkage group 12 of guppy, and identification of a sex specific marker. We generated eight polymorphic microsatellite markers distributed along the distal 5.4 Mbp sequence of the previously identified SD region on linkage group (LG) 12. The markers were tested for association with sex in 156 individuals of the Red Blonde and Flame strains, and 126 progeny of four full-sibs Red Blonde families. A male-specific allele was found for microsatellite gu1066 at position of 25.3 Mbp on LG12 for both strains, and gu832 at position 24.4 Mbp for the Flame strain. Thus, a region of 0.9 Mbp between these markers, harboring 27 annotated genes, was selected for analysis. Based on association of copy number variation and sex determination we mapped a duplicated region between LGs 9 and ...
Recent studies have revealed that the major genes of the mammalian sex determination 43 pathway a... more Recent studies have revealed that the major genes of the mammalian sex determination 43 pathway are also involved in sex determination of fish. Several studies have reported QTL In 44 various species and strains of tilapia, regions contributing to sex determination have been 45 identified on linkage groups 1, 3, and 23. Genes contributing to sex-specific mortality have 46 been detected on linkage groups 2, 6 and 23. To test whether the same genes might control 47
Oreochromis fishes exhibit variability of sex-determination (SD) genes whose characterization con... more Oreochromis fishes exhibit variability of sex-determination (SD) genes whose characterization contributes to understanding of the sex differentiation network, and to effective tilapia farming, which requires all-male culture. However, O. niloticus (On) amh is the only master-key regulator (MKR) of SD that has been mapped (XY/XX SD-system on LG23). In O. aureus (Oa), LG3 controls a WZ/ZZ SD-system that has recently been delimited to 9.2 Mbp, with an embedded interval rich with female-specific variation, harboring two paics genes and banf2. Developing genetic markers within this interval and using a hybrid Oa stock that demonstrates no recombination repression in LG3, we mapped the critical SD region to 235 Kbp on the orthologous On physical map (p < 1.5 × 10−26). DNA-seq assembly and peak-proportion analysis of variation based on Sanger chromatograms allowed the characterization of copy-number variation (CNV) of banf2. Oa males had three exons capable of encoding 90-amino-acid pol...
Various master key regulators (MKRs) that control a binary switch of sex determination (SD) have ... more Various master key regulators (MKRs) that control a binary switch of sex determination (SD) have been found in fish; these provide an excellent model for the study of vertebrate genetic SD. The SD region in flathead grey mullet has been previously mapped to a 1 Mbp region harboring 27 genes, of which one is follicle-stimulating hormone receptor (fshr). Although this gene is involved in gonad differentiation and function, it has not been considered as an MKR of SD. We systematically investigated polymorphism in mullet fshr using DNA shotgun sequences, and compared them between males and females. Capable of encoding nonconservative amino acid substitutions, c.1732G>A and c.1759T>G exhibited association with sex on a population level (N = 83; P ≤ 6.7 × 10−19). Hence, 1732 A and 1759 G represent a male-specific haplotype of the gene, designated as “fshry.” Additional flanking SNPs showed a weaker degree of association with sex, delimiting the SD critical region to 143 nucleotides ...
Differentiation of cells by flow cytometry provides informative somatic cell counts (SCCs) that a... more Differentiation of cells by flow cytometry provides informative somatic cell counts (SCCs) that allow analyzing leukocyte population patterns in udder infections of different etiologies. Postulating that this approach also enhances the statistical power to detect genetic variants linked to cell levels in milk of healthy mammary glands, we used monoclonal antibodies anti-CD18, anti-CD4, anti--CD14, and anti-PMN to count cells presenting these surface antigens, and performed a genome-wide association study of these counts in 125 Israeli Holsteins genotyped using SNP BeadChips. We identified an informative haplotype of 15 SNPs in the centromeric end of BTA3 that was strongly associated with CD18 cells (p < 2.3 × 10−9). Within this region, examination of the network of genes interacting with ITGB2 (CD18) indicated an Fc-γ-receptor gene cluster, including FCGR2A (CD32). Sanger-sequence analysis of FCGR2s-linked exon 3 variation to CD18 counts. Meta-analysis of RNA-Seq data revealed a ...
Background: Crossover localization during meiotic recombination is mediated by the fast-evolving ... more Background: Crossover localization during meiotic recombination is mediated by the fast-evolving zinc-finger (ZnF) domain of gene PRDM9. To study its impact on dairy cattle performance, we compared its genetic variation between the relatively small Israeli (IL) Holsteins and the North American (US) Holsteins that count millions. Results: Initially, we analyzed the major BTA1 haplotypes present in IL Holsteins based on the 10 most telomeric SNPs of the BovineSNP50 BeadChip. Sequencing of representative haplotype carriers indicated that for all frequent haplotypes (> 6%), the variable PRDM9 ZnF array consisted of seven tandem ZnF repeats. Two rare haplotypes (frequency < 4%) carried an indicine PRDM9, whereas all others were variants of the taurine type. These two haplotypes included the minor SNP allele, which was perfectly linked with a previously described PRDM9 allele known to induce unique localization of recombination hotspots. One of them had a significant (p = 0.03) negative effect on IL sire fertility. This haplotype combined the rare minor alleles of the only SNPs with significant (p < 0.05) negative substitution effects on US sire fertility (SCR). Analysis of telomeric SNPs indicated general agreement of allele frequencies (R = 0.95) and of the substitution effects on sire fertility (SCR, R = 0.6) between the US and IL samples. Surprisingly, the alleles that had a negative impact on male fertility had the most positive substitution effects on female fertility traits (DPR, CCR and HCR). Conclusions: A negative genetic correlation between male and female fertility is encoded within the BTA1 telomere. Cloning the taurine PRDM9 gene, which is the common form carried by Holsteins, we encountered the infiltration of an indicine PRDM9 variant into this population. During meiosis, in heterozygous males, the indicine PRDM9 variant may induce incompatibility of recombination hotspots and male infertility. However, this variant is associated with favorable female fertility, which would explain its survival and the general negative correlation (R = − 0.3) observed between male and female fertility in US Holsteins. Further research is needed to explain the mechanism underlying this positive effect and to devise a methodology to unlink it from the negative effect on male fertility during breeding.
Effective farming of tilapia requires all-male culture, characterized by uniformity and high grow... more Effective farming of tilapia requires all-male culture, characterized by uniformity and high growth rate. Males of O. aureus (Oa) and females of O. niloticus (On) produce all-male offspring, but there is a behavioral reproductive barrier between the two species that prevents mass production. In crosses between Oa and On broodstocks, few hybrid females are attracted to the Oa male nests (denoted responders), and if they harbor the On alleles for the sex determination (SD) sites on linkage groups (LGs) 1, 3, and 23, all-male progeny are produced. Yet, without controlling for the alleles underlying SD, the parental stocks gradually lose their capability for all-male production. Hypothesizing that markerassisted selection for female responders would allow production of sustainable broodstocks, we applied genotyping-bysequencing to generate 4983 informative SNPs from 13 responding and 28 non-responding females from two full-sib families. Accounting for multiple comparisons in a genome-wide association study, seven SNPs met a false discovery rate of 0.061. Lowest nominal probabilities were on LGs 9 and 14, for which microsatellite DNA markers were designed within the candidate genes PTGDSL and CASRL, respectively. By increasing the sample size to 22 responders and 47 non-responders and by genotyping additional established microsatellites, we confirmed the association of these LGs with female responsiveness. The combined effects of microsatellites GM171 and CARSL-LOC100690618 on LGs 9 and 14 explained 37% of the phenotypic variance of reproductive interaction (p < 0.0001). Based on these findings, we propose a strategy for mass production of all-male tilapia hybrids through selection for genomic loci affecting SD and female responsiveness.
Background: Sheep production in Israel has improved by crossing the fat-tailed local Awassi breed... more Background: Sheep production in Israel has improved by crossing the fat-tailed local Awassi breed with the East Friesian and later, with the Booroola Merino breed, which led to the formation of the highly prolific Afec-Assaf strain. This strain differs from its parental Awassi breed in morphological traits such as tail and horn size, coat pigmentation and wool characteristics, as well as in production, reproductive and health traits. To identify major genes associated with the formation of the Afec-Assaf strain, we genotyped 41 Awassi and 141 Afec-Assaf sheep using the Illumina Ovine SNP50 BeadChip array, and analyzed the results with PLINK and EMMAX software. The detected variable genomic regions that differed between Awassi and Afec-Assaf sheep (variable genomic regions; VGR) were compared to selection signatures that were reported in 48 published genome-wide association studies in sheep. Because the Afec-Assaf strain, but not the Awassi breed, carries the Booroola mutation, association analysis of BMPR1B used as the test gene was performed to evaluate the ability of this study to identify a VGR that includes such a major gene. Results: Of the 20 detected VGR, 12 were novel to this study. A ~7-Mb VGR was identified on Ovies aries chromosome OAR6 where the Booroola mutation is located. Similar to other studies, the most significant VGR was detected on OAR10, in a region that contains candidate genes affecting horn type (RXFP2), climate adaptation (ALOX5AP), fiber diameter (KATNAl1), coat pigmentation (FRY) and genes associated with fat distribution. The VGR on OAR2 included BNC2, which is also involved in controlling coat pigmentation in sheep. Six other VGR contained genes that were shown to be involved in coat pigmentation by analyzing their mammalian orthologues. Genes associated with fat distribution in humans, including GRB14 and COBLL1, were located in additional VGR. Sequencing DNA from Awassi and Afec-Assaf individuals revealed non-synonymous mutations in some of these candidate genes. Conclusions: Our results highlight VGR that differentiate the Awassi breed from the Afec-Assaf strain, some of which may include genes that confer an advantage to Afec-Assaf and Assaf over Awassi sheep with respect to intensive sheep production under Mediterranean conditions.
Investigative ophthalmology & visual science, Mar 1, 2017
Applying CNGA3 gene augmentation therapy to cure a novel causative mutation underlying achromatop... more Applying CNGA3 gene augmentation therapy to cure a novel causative mutation underlying achromatopsia (ACHM) in sheep. Impaired vision that spontaneously appeared in newborn lambs was characterized by behavioral, electroretinographic (ERG), and histologic techniques. Deep-sequencing reads of an affected lamb and an unaffected lamb were compared within conserved genomic regions orthologous to human genes involved in similar visual impairment. Observed nonsynonymous amino acid substitutions were classified by their deleteriousness score. The putative causative mutation was assessed by producing compound CNGA3 heterozygotes and applying gene augmentation therapy using the orthologous human cDNA. Behavioral assessment revealed day blindness, and subsequent ERG examination showed attenuated photopic responses. Histologic and immunohistochemical examination of affected sheep eyes did not reveal degeneration, and cone photoreceptors expressing CNGA3 were present. Bioinformatics and sequenci...
As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusiv... more As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.
As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusiv... more As from January 2010 The Israeli Journal of Aquaculture-Bamidgeh (IJA) will be published exclusively as an on-line Open Access (OA) quarterly accessible by all AquacultureHub (http://www.aquaculturehub.org) members and registered individuals and institutions. Please visit our website (http://siamb.org.il) for free registration form, further information and instructions. This transformation from a subscription printed version to an on-line OA journal, aims at supporting the concept that scientific peer-reviewed publications should be made available to all, including those with limited resources. The OA IJA does not enforce author or subscription fees and will endeavor to obtain alternative sources of income to support this policy for as long as possible.
Recent studies have revealed that the major genes of the mammalian sex determination pathway are ... more Recent studies have revealed that the major genes of the mammalian sex determination pathway are also involved in sex determination of fish. Several studies have reported QTL In various species and strains of tilapia, regions contributing to sex determination have been identified on linkage groups 1, 3, and 23. Genes contributing to sex-specific mortality have been detected on linkage groups 2, 6 and 23. To test whether the same genes might control sex determination in mammals and fishes, we mapped 11 genes that are considered as putative master key regulators of sex determination: Amh,
segregation of body and peritoneum ptgmentation was studied in three developmental stages in F2 h... more segregation of body and peritoneum ptgmentation was studied in three developmental stages in F2 hybrids and progeny or ri nvoriJr nac[crosseo with parents oreochromis aureus (black body and
Specific antisera against red blood cells of some tilapia species were obtained by reciprocal int... more Specific antisera against red blood cells of some tilapia species were obtained by reciprocal interspecific and intergeneric immunizations. The antisera were used to confirm co-dominant expression of epitopes in F 1 interspecific hybrids and to identify the parental origin of three red tilapia strains. The antisera in all hybrids (Oreochromis niloticus x O. mossambicus, O. aureus x O. hornorum, O. niloticus x S. galilaeus and O. niloticus x O. aureus) were positive to both parental strains. However, while all F 1 hybrids of O. mossambicus x O. hornorum were positive to anti-O. mossambicus antiserum, only 50% were positive to anti-O. hornorum antiserum. In most cases, these results point to co-dominant expression of the species-specific epitopes in hybrids. In addition, the triple parental origins of the Philippine red tilapia (positive for O. aureus, O. mossambicus and O. niloticus epitopes) and of mossambicus red tilapia (positive for O. hornorum, O. mossambicus and O. niloticus epitopes) were assessed. The O. niloticus red tilapia, described as a purebred red variant of O. niloticus, was positive for both anti-O. niloticus and anti-O. aureus antibodies, with a significantly more intense reaction to the latter. A possible genetic basis of this last finding is discussed.
A bimodal distribution in the spontaneous chemiluminescence (SpCL) measurements in naive tilapia ... more A bimodal distribution in the spontaneous chemiluminescence (SpCL) measurements in naive tilapia leads us to divide the fish into low and high responder groups. Because of the homogeneity in both differential phagocyte cell counts and stimulation indexes, it is suggested that diffeiencei between the responder groups are due to innate intrinsic factors. Difference between these two groups is also displayed, in a less significant manner, in zymosan stimulated chemiluminescence (zStCL) that showed a weak linear regression factor (R2=0.4756). ln naive Iilapia, Streptococcus difficile bacterin-stimulated chemiluminescence (bStCL) values were much lowerthan those obtained in zStCL. When sibling fish were infected with live S. difficite bacteria, a spectacular increase in bStCL values, with a high stimulation index of 4.2, was displayed on day 6 after infection. The SpCL and bStCL values increased considerably in diseased fish which displayed a serious symptomatology on day 36 after infection. However, fish that developed resistance to the disease showed lowered values in both SpCL and bStCL. The implication of these f indings in the in vivo production of reactive oxygen radicals by phagocytic cells and their connection to resistance and susceptibility to disease are discussed in comparison to mammals.
Production of viable diploid mitogynogenetic tilapias was achieved using Oreochromis aureus eggs ... more Production of viable diploid mitogynogenetic tilapias was achieved using Oreochromis aureus eggs collected from a third generation of meiogynogenetic females, fertilized with UV-irradiated sperm of red tilapia. Diploidy was restored by cold shock treatment (1 h at 1 1'C) stafting at the zygotic age of 77 min. Mitogynogens could be identif ied at embryo and juvenile ages on the basis of their body pigmentation, which clearly differentiated them from normal hybrid controls which showed the presence of paternally inherited red and yellow chromatophores. Because of asynchronization in cell divisions, assessed during the first, second and third cell division periods, maximal increment cleavage times (MICT) were defined within these periods. Intervals between MICT's define a cell cycle length of exactly 28 min between these cleavages performed a|28.2+0.2'C and of 75 min between the second meiotic and first mitotic divisions. The optimal cleavage blocking time (OCBT), which leads to diploidization when cold shock is applied, could be defined as occurring 2 min before MICT following shocking of embryo groups at different intervals of time before and after MICT. Because MICT is separated by only 2 min from OCBT, it is suggested that furrow appearance, namely the contractile ring formation, is directly influenced by cold shock rather than the spindle chromosome separation mechanism.
Poecilia reticulata is one of the most popular ornamental fish species with a higher demand for m... more Poecilia reticulata is one of the most popular ornamental fish species with a higher demand for males due to their large colorful fins. The objectives of this study were mapping of the sex-determining (SD) region on linkage group 12 of guppy, and identification of a sex specific marker. We generated eight polymorphic microsatellite markers distributed along the distal 5.4 Mbp sequence of the previously identified SD region on linkage group (LG) 12. The markers were tested for association with sex in 156 individuals of the Red Blonde and Flame strains, and 126 progeny of four full-sibs Red Blonde families. A male-specific allele was found for microsatellite gu1066 at position of 25.3 Mbp on LG12 for both strains, and gu832 at position 24.4 Mbp for the Flame strain. Thus, a region of 0.9 Mbp between these markers, harboring 27 annotated genes, was selected for analysis. Based on association of copy number variation and sex determination we mapped a duplicated region between LGs 9 and ...
Recent studies have revealed that the major genes of the mammalian sex determination 43 pathway a... more Recent studies have revealed that the major genes of the mammalian sex determination 43 pathway are also involved in sex determination of fish. Several studies have reported QTL In 44 various species and strains of tilapia, regions contributing to sex determination have been 45 identified on linkage groups 1, 3, and 23. Genes contributing to sex-specific mortality have 46 been detected on linkage groups 2, 6 and 23. To test whether the same genes might control 47
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Papers by Andrey Shirak