Exam 2 evolution terms

Homeotic

Genes that regulate spatial and temporal patterning

Homeotic loci

Genes of large effect

Homeotic gene complexes

Code for transcription factors that regulate expression of other genes

Colinearity

the linear arrangement of genes on a chromosome, where the order of nucleotides in a gene directly corresponds to the order of amino acids in the protein it encodes

What are the three parts of the tetrapod limbs

Stylopod, zeugopod, autopod

What was the first organism to show signs of terrestrial limbs?

Panderichthyidae

Apical extodermal ridge (AER)

A structure that forms from ectodermal cells at the distal end of the limb bud, acting as a signaling center during limb development

Zone of polarizing activity (ZPA)

a specific region in the limb bud that acts as a signaling center along the anteroposterior axis of the limb

What regulates ZPA?

Sonic hedgehog (shh)

What regulates AER?

Fibroblast growth factor 2 (FGF-2)

What are the assumptions of Hardy-Weinberg equilibrium?

No selection, mutation, migration, genetic drift. There is also random mating and diploid and sexual reproduction

Selection against recessive

Gene frequencies change rapidly at first but as the recessive becomes rare and masked in the heterozygote, rate of evaluation slows

Complete dominance

Heterozygote fitness equal to that of homozygous dominant

No dominance

Heterozygote intermediate to that of either homozygote

Overdominance

Heterozygote superiority

Underdominance

Selection against heterozygote

Mutation-selection balance

Removal by selection offsets recurrent mutations

Migration

Movements of individuals among population

Gene flow

Movement of alleles

Effective population size (N_e)

Number of individuals in a population that reproduce

Genetic drift

Chance fluctuations in gene frequencies between generations

Panmictic population

Large randomly mating population

Inbreeding

Indivduals may choose to mate with genetic relatives

Hypothesis testing

The most direct method for discerning among multiple possible explanations for a phenomenon

What are the limits on adaptations

Time lags, genetic constraints, developmental constraints, functional constraints, and trade offs