Evo Devo Flashcards
(27 cards)
What is ontogeny?
process of unicellular zygotes becoming multicellular and then reproducing adults
What is embryogenesis?
growth and development of the embryo
What is an embryo, and what does it mediate?
stage between fertilization and birth; mediates genotype and phenotype
What is the recapitualtion hypothesis/ biogenetic law?
tendency for embryonic development to reveal evolutionary history of animals
How does modern research approach developmental biology?
modern approach includes molecular and morphological studies, as well as experimental biology
What is evo-devo?
evolutionary study of the spatial and temporal expression of genes that control body architecture among metazoans
What are transcription factors?
products of genes involved in controlling early development
What do transcription factors define?
defines the embryonic body axes, directionality of structures, and appearance of structures/ body cavity/ segments/ appendages organization
what three genetic factors were expected to exist in unicellular ancestors?
tendency for cells to aggregate rather than disperse after mitosis
biochemical ability for cells to remain together as a group
movement or differentiation of cells bearing one set of specialization in response to proximity with cells bearing another set
What are developmental tool kits?
sets of functional genes that control ontogenetic processes
Three developmental tool kits
adhesion of cells to another
cell signaling pathways
differentiation of cells from primordial to specialized states
What are cell signaling pathways?
transduction of biochemical signals within and between cell types
What are orthologs?
homologous gene sequences in different species
Examples of orthologs in choanoflagellates (2)
CF structure and genomic studies support ancestry
CF express adhesion and cell signaling homologues
What are hox clusters?
groups of homeotic genes that control the body plan and limb organization of developing embryos along their anterior-posterior axis
WHat is an example of hox clusters?
brachyury gene, defining midline and notochord of chordata
What are two examples of homologous hox genes not expressed in the same way?
arrangement is not always linear
can exhibit homoplasy/ convergent evolution through sequence and function
What is developmental system drift?
developmental drift evolving in unexpected ways
performs a function in one group and co-opted for another in a different group (begins through gene duplication)
What can developmental system drift be used for?
can be used to track evolution of particular structures
Example of a developmental system drift
Pax6 is used in eye and eyeless bilatarians, meaning it has been co-opted for something other than eye development
How do difference in gene expression arise?
epistasis occurring within different genetic backgrounds
What is a gene regulatory network?
groups of genes responsible for producing functional traits
Four examples of gene regulatory networks
cell differentiation networks
subcircuits
switches
kernels
What are subcircuits?
developmental gene networks used in cell function
