FINAL - New Stuff Flashcards
(98 cards)
Found that early embryonic stages of different vertebrates have features in common that they would lose later in development
Von Baer
Von Baer
Comparative Animal Development
Early in development, a human is virtually indistinguishable from:
an alligator or mouse
Embryos of _____, _______ and ______ develop _______ that are resorbed and lacking in adults
birds
anteaters
baleen whales
incipient teeth
Human embryos grow a _____ that persists as _______; some infants are born with
tail
3 fused sacral vertebrae
complete tails
wnt-3a gene, Chr 1
Gene that controls tail growth
Range of tail length’s in humans
1-12” long
As in other primates, human fetuses develop ________; normally shed before birth but sometimes present at birth
dense coat of hair (Lanugo)
Comparative animal development provides evidence for:
evolution of diverse spp. from common ancestors
Differential rate of growth of different parts or dimensions of an organisms during ontogeny
Allometric growth
Allometric growth examples:
An elephant’s tusks are incisor teeth that have grown faster and for a longer time than other teeth
Male stag beetle shows positive allometry of mandibles, relative to body size
In 1970/80’s, discovery of the ______ of ______ genes in animals marked down of modern evo-devo
Hox cluster
homeobox
Homeobox genes
Direct development of the animal from the front end all the way to the back
Homeobox genes are a class of ________ that control patterning of specific body structures
homeotic selector genes
Homeobox genes control identity of segments along _______ body axis of animals
anterior-posterior
The same “toolkit” of genes and developmental pathways are _____ in the vast diversity of organisms
conserved
Mutations in Hox genes
Homeotic mutations
Mutations in Hox genes cause ________ of one type of ______ into another
transformations
segment
Hox mutations in what spp:
drosophila
Mapping p/a of ______ on animal tree of life shows _______________
Hox genes
common evolutionary history
______ sets stage for further study of commonalities among animals in _______ patterning and limb development
Mapping of Hox genes
dorsal-ventral
Fluorescent visualization methods reveal that _______ are expressed in _____________
Hox genes
spatially restricted regions
Under normal conditions:
Antennapedia gene expressed only in first segment of thorax
Under mutated conditions:
antennapedia gene can have a gain of function mutation that causes an antenna to leg transformation