Ch 12 Human Genetics

Chapter 12: Human Genetics Humans: • 23 Pairs of Chromosomes (22 Autosomes and 1 Sex) • 46 Individual Chromosomes • Sex: X and Y (female: XX) ( male: XY) o 50/50 Chance of either sex (determined by sperm • Mutations: mistakes on or in chromosomes (not always bad) o Some good and some bad Chromosomal Mutations: • Usually during Interphase while chromosomes are long and thin, and replicating himself 1. Deletion: loss of an allele 2. Duplication: an allele is duplicated twice 3. Inversion: alleles are reversed 4. Translocation: alleles break off and attach to another chromosome Gene • 1. 2.

Mutations: Mistakes on the allele Point Mutations: one of the base pairs is switched; out of order Frame Shift: Base pairs are not read correctly

Nondisjunction: • Failure of the tetrads to separate during meiosis (one cell has too many and one too few) 1. Down Syndrome: extra 21st chromosome • Thick tongue, webbing between fingers and neck, mentally retarded 2. Turner’s Syndrome: lack of an X chromosome in females (XO) • Sterile, short 3. Klinfelter’s Syndrome: sperm has X and Y (XXY) • Male, low IQ, sex organs of both sexes, sterile Sex-linked Traits: • Carried on X or Y chromosomes • Colorblindness: found chromosome •

Hemophilia: bleeder’s found on the X chromosome

Normal Female: XC XC Normal Male: XC Y Carrier Female: XC Xc Colorblind Male: Xc Y c c Colorblind Female: X X Normal Female: XH XH Carrier Female: XH Xh Bleeder Female: XhXh

Normal Male: XH Y Bleeder Male: XhY

on the X disease;

Blood Types: • A: (IA IA) or (IA i) • B: (IB IB) or (IB i) • AB: (IA IB) • O: (i i)