Thomas Kocher

About

Thomas Kocher is a professor in the Department of Biology at the University of Maryland. His research focuses on understanding the evolutionary forces that have caused rapid speciation within Lake Malawi cichlid fishes, with more than 700 species arising within the last million years. He aims to identify the genes responsible for phenotypic traits associated with speciation, such as jaw morphology, color pattern, sex determination, and mate preferences, and to study the geographic distribution of allelic variants among wild populations. Kocher teaches courses including Principles of Genetics and Genetic Research on Cichlid Fishes. His educational background includes a B.A. from Yale University and a Ph.D. from the University of Colorado. His research contributions include elucidating sex chromosome systems in basal Haplotilapiine cichlids, identifying supergenes for sex and color in Lake Malawi cichlids, and investigating the structure and evolution of sex chromosomes across various fish species. His work advances understanding of the genetic mechanisms underlying speciation, sex determination, and biodiversity in fishes.

Research topics

• Statistics
• Ecology
• Paleontology
• Evolutionary biology
• Genetics
• Biology

Selected publications

• Nile Tilapia: A Model for Studying Teleost Color Patterns

  Journal of Heredity · 2021-04-08 · 62 citations

  articleOpen accessCorresponding

  The diverse color patterns of cichlid fishes play an important role in mate choice and speciation. Here we develop the Nile tilapia (Oreochromis niloticus) as a model system for studying the developmental genetics of cichlid color patterns. We identified 4 types of pigment cells: melanophores, xanthophores, iridophores and erythrophores, and characterized their first appearance in wild-type fish. We mutated 25 genes involved in melanogenesis, pteridine metabolism, and the carotenoid absorption a…

  PublisherOA PDFDOI

• Loss of Cyp11c1 causes delayed spermatogenesis due to the absence of 11-ketotestosterone

  Journal of Endocrinology · 2020-01-07 · 51 citations

  article

  The impacts of androgens and glucocorticoids on spermatogenesis have intrigued scientists for decades. 11β-hydroxylase, encoded by cyp11c1, is the key enzyme involved in the synthesis of 11-ketotestosterone and cortisol, the major androgen and glucocorticoid in fish, respectively. In the present study, a Cyp11c1 antibody was produced. Western blot and immunohistochemistry showed that Cyp11c1 was predominantly expressed in the testicular Leydig cells and head kidney interrenal cells. A mutant lin…

  PublisherDOI

• Ecomorphological divergence and habitat lability in the context of robust patterns of modularity in the cichlid feeding apparatus

  BMC Evolutionary Biology · 2020 · 41 citations

  BACKGROUND: Adaptive radiations are characterized by extreme and/or iterative phenotypic divergence; however, such variation does not accumulate evenly across an organism. Instead, it is often partitioned into sub-units, or modules, which can differentially respond to selection. While it is recognized that changing the pattern of modularity or the strength of covariation (integration) can influence the range or rate of morphological evolution, the relationship between shape variation and covaria…

  DOI

• Dmrt1 is the only male pathway gene tested indispensable for sex determination and functional testis development in tilapia

  PLoS Genetics · 2024-03-27 · 32 citations

  articleOpen accessCorresponding

  Sex is determined by multiple factors derived from somatic and germ cells in vertebrates. We have identified amhy, dmrt1, gsdf as male and foxl2, foxl3, cyp19a1a as female sex determination pathway genes in Nile tilapia. However, the relationship among these genes is largely unclear. Here, we found that the gonads of dmrt1;cyp19a1a double mutants developed as ovaries or underdeveloped testes with no germ cells irrespective of their genetic sex. In addition, the gonads of dmrt1;cyp19a1a;cyp19a1b…

  PublisherOA PDFDOI

• Knockout of Hermansky-Pudlak Syndrome 4 (hps4) leads to silver-white tilapia lacking melanosomes

  Aquaculture · 2022-05-30 · 23 citations

  article
  PublisherDOI

Recent grants

• NIH Grant R01HD058635

  NIH · $1.3M · 2012

• Genomic Architecture of an Adaptive Radiation

  NSF · $910k · 2012–2016

• Color, Sex and Speciation of Lake Malawi Cichlid Fishes

  NSF · $586k · 2005–2008

Frequent coauthors

• Matthew A. Conte

  Walter Reed Army Institute of Research

  49 shared

• Jay R. Stauffer

  Pennsylvania State University

  30 shared

• Jean‐François Baroiller

  Centre de Coopération Internationale en Recherche Agronomique pour le Développement

  29 shared

• Hélèna D'Cotta

  28 shared

• Kenneth R. McKaye

  United Nations University World Institute for Development Economics Research

  25 shared

• Deshou Wang

  Southwest University

  25 shared

• Karen L. Carleton

  23 shared

• William Gammerdinger

  Harvard University

  22 shared

Education

• NIH Postdoctoral Fellow, Biochemistry

  University of California Berkeley

  1989

• PhD, EPO Biology

  University of Colorado Boulder

  1986

• BA, Biology

  Yale University

  1981

Similar researchers at University of Maryland, College Park

• Joshua Weitzh-65
• Jonathan Simonh-51
• Sergei Sukharevh-49