BIOL 443 Lecture Notes - Lecture 2: Genetic Recombination, Alternative Splicing, Chromatin
Document Summary
Evolutionary embryology: da(cid:396)(cid:449)i(cid:374) a(cid:374)d othe(cid:396)s k(cid:374)e(cid:449) (cid:448)o(cid:374) bae(cid:396)"s la(cid:449)s, a(cid:374)d i(cid:374)(cid:272)o(cid:396)po(cid:396)ated the(cid:373) i(cid:374)to evolutionary theory. Similarities in embryo structure indicate an evolutionary relationship, even if adult forms are extremely different: embryonic homologies. Homologous structures are those organs whose underlying similarity arises from their being derived from a common ancestral structure. Wings of birds and bats, flippers of seals, and arms of humans are all forelimbs. They all derived from a common ancestral structure. Analogous structures are those whose similarity comes from performing a similar function rather than arising from a common ancestor. Medical embryology and teratology different ancestor: between 2 and 5% of human babies have visible birth defects caused by developmental defects. An overactive version of the fgfr3 receptor protein causes cartilage cells to stop dividing prematurely, resulting in dwarfism: disruptions and teratogens. Thalidomide (motion sickness drug) causes deficient or absent limbs, heart defects, absence of external ears, and malformed intestines, depending on when taken during pregnancy.
