BIOL 2081C Lecture Notes - Lecture 18: Dichromacy, Trichromacy, Opsin
Document Summary
Reading assignment: hartl text, sections 8. 1 8. 3. Required web assignment (both very short pages): https://www. ncbi. nlm. nih. gov/class/nawbis/modules/phylogenetics/phylo10. html and http://evolution. berkeley. edu/evolibrary/article/side_o_0/complexnovelties_01. Missing a chromosome from a pair: monosomy. Has more than two chromosomes of a pair: trisomy, tetrasomy, etc: numerical abnormalities of the sex chromosomes. 47, xxx: female with 3 x chromosomes. 48,xxyy: variant of klinefelter syndrome: numerical abnormalities of the autosomes (+) and (-) used to designate constitutionals. 48,xx,+18+21: females with both trisomy 18 and trisomy 21. 46,xy,+21c,-21: male trisomy 21 patient with loss of one chromosome 21 in his tumor cells. A calico cat has black and orange splotches. 100% females will be calico, 50% males will be black, 50% males will be orange. Implications of extra or missing autosomes: most monosomies do not result in viable pregnancies, there are a few trisomies, but only one is viable long-term, trisomy 21. Implications of extra or missing sex chromosomes: dosage compensation: all but one x chromosome is inactivated.
