As single-celled zygotes, all animals start life looking much the same. Through the process of development, these initially nondescript cells give rise to the millions of distinct animal species which populate our planet. The central question in the field of Evolutionary Developmental Biology is how natural selection has altered the process of development to yield the stunning diversity which surrounds us.
In my lab, we are interested in understanding the evolution of our own subphylum, the vertebrates. To do this, we study developmental gene expression, regulation, and function in three model organisms; lamprey, amphioxus, and zebrafish. Lamprey, a jawless vertebrate, is the most basal vertebrate amenable to experimental manipulation at embryonic stages. Amphioxus is the most basal extant chordate and is thought to closely resemble the invertebrate ancestor of the vertebrates. Zebrafish, a teleost, is one of the most experimentally tractable vertebrate model systems. By comparing lamprey and amphioxus development with that of zebrafish, and other vertebrates like frog and salamander, we aim to reconstruct the genetic and developmental changes underlying the earliest events in vertebrate evolution. |
What is Evo-Devo?
Development is the process by which single-celled zygotes become multicellular organisms. Alterations in the developmental program often lead to differences in adult morphology. When these alterations are beneficial, they become fixed in a population and can drive the evolution of new phyla. The field of Evolutionary Developmental Biology or “The Evolution of Development” (Evo-Devo) seeks to understand how new groups arise by understanding how the process of development has evolved in different lineages. While both “Evo-Devo” and “Developmental Biology” have their roots in traditional Embryology, modern Developmental Biology focuses on understanding the developmental genetic mechanisms of normal development in a small number of model organisms (horizontal arrows in the drawing). Evo-Devo applies the key findings and techniques of Developmental Biology and genetics to a wider phylogenetic sampling to elucidate the developmental genetic bases of evolutionary change (vertical arrow in the diagram). |
Model Organisms
Sea Lamprey (Petromyzon marinus)
Lamprey is a jawless (agnathan) vertebrate in the superclass Cyclostomata, meaning that they and the hagfish are sister to all other vertebrates. It is the most amenable agnathan to experimental manipulation at embryonic stages. As a living member of the group which includes the very first vertebrates, lamprey is thought to retain many features of the vertebrate ancestor. Amphioxus (Branchiostoma floridae)
Amphioxus is an invertebrate chordate and the only living member of the subphylum cephalochordata. Amphioxus shares key morphological, developmental, genetic, and genomic traits with vertebrates--features absent or lost in other invertebrate chordates (i.e. Urochordates). Because of its vertebrate affinities and basal phylogenetic position, amphioxus is considered a good living approximation of both the pre-vertebrate chordate and the first chordate. |
Zebrafish (Danio rerio)
Zebrafish is a small, fast-developing teleost fish and one of the main genetic models for vertebrate development. Zebrafish is highly amenable to early embryonic manipulations, including gene-knockdown, mRNA overexpression, and gene-regulatory analyses. African Clawed Frog (Xenopus laevis)
The african clawed frog is a model system for both developmental and cell biology. Xenopus embryos are large, easy to raise in the lab, and experimentally tractable. |
Contact Our Lab
Daniel Meulemans Medeiros
Department of Ecology and Evolutionary Biology (EBIO)
Ramaley N122 Campus Box 334
University of Colorado
Boulder, CO 80309-0334
Office: Ramaley C271
Office phone: (303) 492-6180
Lab phone: (303) 735-1984
EBIO Fax: (303) 492-8699
email: [email protected]
Department of Ecology and Evolutionary Biology (EBIO)
Ramaley N122 Campus Box 334
University of Colorado
Boulder, CO 80309-0334
Office: Ramaley C271
Office phone: (303) 492-6180
Lab phone: (303) 735-1984
EBIO Fax: (303) 492-8699
email: [email protected]