The Human Genome Chapter 14

Human Chromosomes Humans have 46 chromosomes 23 from mom, 23 from dad - form homologous pairs 44 Autosomes 2 sex chromosomes 46,XX or 46,XY

Karyotypes

What if something goes wrong?

What is nondisjunction? Random event, not inherited trait

Translocation – pieces of chromosomes moved to other chromosomes Trisomy – one extra chromosome: Down syndrome (Trisomy 21), Kleinfelter’s syndrome 47, XXY Monosomy – missing one chromosome Turner’s syndrome(45, X)

Pedigrees

Genes and the Environment Polygenic traits – many human traits are controlled by more than one gene Nutrition Exercise How does the environment affect your phenotype “Nature vs. Nurture”

Human Genes There are nearly 30,000 human protein-coding genes in the human genome Identification of genes that control blood type one of the first human genes to be identified Codominant, multiple alleles

Blood Typing

Genetic Disorders (pg. 345)-inherited

Sex-Linked Genes More than 100 genetic disorders mapped to the X chromosome Y is much smaller with only a few genes

Sex-Linked Disorders Colorblindness Hemophilia Duchenne Muscular Dystrophy