Skip to main content
C. Sarah Cohen
  • Romberg Tiburon Center for Environmental Studies, San Francisco State University

C. Sarah Cohen

Evolutionary developmental biology (evo-devo) has undergone dramatic transformations since its emergence as a distinct discipline. This paper aims to highlight the scope, power, and future promise of evo-devo to transform and unify... more
Evolutionary developmental biology (evo-devo) has undergone dramatic transformations since its emergence as a distinct discipline. This paper aims to highlight the scope, power, and future promise of evo-devo to transform and unify diverse aspects of biology. We articulate key questions at the core of eleven biological disciplines-from Evolution, Development, Paleontology, and Neurobiology to Cellular and Molecular Biology, Quantitative Genetics, Human Diseases, Ecology, Agriculture and Science Education, and lastly, Evolutionary Developmental Biology itself-and discuss why evo-devo is uniquely situated to substantially improve our ability to find meaningful answers to these fundamental questions. We posit that the tools, concepts, and ways of thinking developed by evo-devo have profound potential to advance, integrate, and unify biological sciences as well as inform policy decisions and illuminate science education. We look to the next generation of evolutionary developmental biolo...
Little is known about the number and rate of introductions into terrestrial and marine tropical regions, and if introduction patterns and processes differ from temperate latitudes. Botryllid ascidians (marine invertebrate chordates) are... more
Little is known about the number and rate of introductions into terrestrial and marine tropical regions, and if introduction patterns and processes differ from temperate latitudes. Botryllid ascidians (marine invertebrate chordates) are an interesting group to study such introduction differences because several con- geners have established populations across latitudes. While temperate botryllid invasions have been repeatedly highlighted, the global spread of tropical Botryl- loides nigrum (Herdman, 1886) has been largely ignored. We sampled B. nigrum from 16 worldwide warm water locations, including around the Panama Canal, one of the largest shipping hubs in the world and a possible introduction corri- dor. Using mitochondrial (COI) and nuclear (ANT) markers, we discovered a single species with low genetic divergence and diversity that has established in the Atlantic, Pacific, Indo-Pacific, and Mediterranean Oceans. The Atlantic Ocean contained the highest diversity and multilocus theta estimates and may be a source for introductions to other regions. A high frequency of one mito- chondrial haplotype was detected in Pacific populations that may represent a recent introduction in this region. In comparison to temperate relatives, B. ni- grum displayed lower (but similar to temperate Botrylloides violaceus) genetic divergence and diversity at both loci that may represent a more recent global spread or differences in introduction pressures in tropical regions. Additionally, chimeras (genetically distinct individuals sharing a single body) were detected in three populations by the mitochondrial locus and validated using cloning, and these individuals contained new haplotype diversity not detected in any other colonies.
The purpose of this study is to analyze trends in environmental conditions in the San Francisco Bay and to determine whether these environmental factors have a significant impact on organismal growth. This study analyzed temperature,... more
The purpose of this study is to analyze trends in environmental conditions in the San Francisco Bay and to determine whether these environmental factors have a significant impact on organismal growth. This study analyzed temperature, salinity, and ocean current data collected from six different field sites located in the central region of the San Francisco Bay throughout July, 2010. This environmental data was compared to organismal growth on recruitment devices at each site. The recruitment devices consisted of two 6”x12” PVC plates and one mesh wrap containing two Tuffy kitchen scrub pads. Settled organisms included native and invasive crustaceans, bryozoans, polychaetes, nudibranchs, and tunicates. Protected field sites in the East Bay experiencing maximum currents between 20-30 cm/s and average temperatures of 18.2-18.4 °C demonstrated the most overall organismal growth. The relationship between variation in salinity and organismal growth is unclear and further study addressing ...
The direct developmental mode and sedentary habit of Leptosynapta clarki (Heding), an infaunal, brooding holothuroid, suggest that this species has limited dispersal capabilities. Using starch gel electrophoresis, we estimated allele... more
The direct developmental mode and sedentary habit of Leptosynapta clarki (Heding), an infaunal, brooding holothuroid, suggest that this species has limited dispersal capabilities. Using starch gel electrophoresis, we estimated allele frequencies at two polymorphic enzyme ...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their... more
A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms.