The Human Genome Ch. 14
Human Chromosomes Karyotype = how chromosomes are arranged in pairs Humans have 46 chromosomes or 23 pairs The 23rd pair are the sex chromosomes XY = male XX = female The other 22 pair are called autosomes
Human Traits Pedigrees are a chart that shows the relationships within a family as it relates to a certain trait Circle = female Square = male
Autosomal Disorders Caused by Recessive alleles Dominant alleles Cystic fibrosis Dominant alleles Achondroplasia Codominant alleles Sickle cell disease
Sex-linked Genes Colorblindness Hemophilia Duchene Muscular Dystrophy Males have just 1 X chromosome – so all sex linked alleles are expressed in males even if they are recessive
Chromosomal Disorders Nondisjunction = chromosomes don’t separate correctly Down syndrome 3 copies of the 21st chromosome