1. Human Chromosomes

2. How many chromosomes do humans have? 46 In 23 pairs – one in each pair from mom, one from dad Matched pair = homologous chromosomes They have the same genes in the same order (but not necessarily the same alleles)

3. Homologous Chromosomes One in each pair from mother, the other from father Homologous pairs carry genes controlling the same inherited traits. Each locus (position of a gene) is in the same position on homologues.

4. Homologous Chromosomes Eye color locus Hitchhiker thumb locus

5. Karyotype A karyotype is an organized profile of a person's chromosomes. In a karyotype, --chromosomes are arranged and numbered by size, from largest to smallest. --used to find genetic diseases caused by chromosome problems To make a karyotype, scientists take a picture of someone's chromosomes, cut them out and match them up

6. Humans have 23 Sets of Homologous Chromosomes Each Homologous set is made up of 2 Homologues. Homologue

7. Autosomes (The Autosomes code for most of the offspring’s traits) In Humans the “Autosomes” are sets 1 - 22

8. Sex Chromosomes

9. Sex Chromosomes The Sex Chromosomes code for the sex of the offspring. ** If the offspring has two “X” chromosomes it will be a female. ** If the offspring has one “X” chromosome and one “Y” chromosome it will be a male. XX chromosome - femaleXY chromosome - male In Humans the “Sex Chromosomes” are the 23 rd set X chromosome Y chromosome