BIOL1006 Lecture Notes - Lecture 7: Genetic Counseling, Mendelian Inheritance, Sister Chromatids
Document Summary
Lect 7 gene disorders - mostly very rare, recessive mutations - source of all new alleles. Tay-sachs disease - causes lysosomes to burst frequency of disease can vary w/ different populations and different histories highest chance in jewish populations natural selection can"t always get rid of all gene disorders. Huntington disease - disorder caused by dominant gene clinical symptoms don"t appear until middle age those w/ disease have time to reproduce natural selection doesn"t get rid of it. Rh blood group - cell surface markers on human red blood cells. Sry gene - on y chromosome, plays important role in male sexual development environmental factors can cause changes in sex of adult fishes/reptiles. Barr body - inactive x chromosome in females (deactivated after sex is determined) gap conversion - copies over dna sequence from other chromosome. Dna sections that don"t match are completely discarded. Y chromosome consists of palindromes, able to fix itself w/o another.
