BIOL207 Lecture Notes - Lecture 37: Monosomy, Down Syndrome, Trisomy

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL207
• Professor: Michael Harrington

Document Summary

Change in chromosome number: pseudo autosomal regions in x and y chromosomes. Before x and y differentiated they used to be homologues like autosomes. Overtime, y chromosome lost most of its genes. But x and y still share some common regions hence they can crossover during meiosis. Pseudoautosomal region: common regions that contain similar genes and allow pairing up. Genes in this region behave like autosomes and are not inherited in a sex-linked pattern. One of the genes in this region is the shox gene. Shox gene is a protein that promotes bone growth. 46xx and 46xy have two copies of these genes and hence average height. 47xyy or 47xxx are taller than average. 45x are short- turner syndrome in women: polyploidy notation: (cid:858)(cid:272)(cid:859): dna (cid:272)o(cid:374)te(cid:374)t i(cid:374) a (cid:272)ell (cid:858)(cid:374)(cid:859): (cid:374)u(cid:373)(cid:271)er of (cid:272)o(cid:373)plete sets of (cid:272)hro(cid:373)oso(cid:373)es. Whe(cid:374) des(cid:272)ri(cid:271)i(cid:374)g pol(cid:455)ploids (cid:449)e use the letter (cid:858)(cid:454)(cid:859) i(cid:374)stead of (cid:858)(cid:374)(cid:859) For a diploid, n= x and 2n= 2x.