Human Genetics

Chromosomes

• Condensed form of our DNA.

  • Contains our genes!

• We dye them to create bands at specific pairs.

  • We do this to see the chromosomes more clearly.

• The bands DO NOT represent single genes.

• The thinnest band contains over a million base pairs and potentially hundreds of genes

Types of Chromosomes

• Humans have 46 chromosomes, 23 pairs total.

  • 2 chromosomes are sex chromosomes (X and Y)

  • The remaining 44 are autosomal chromosomes or autosomes.

• Chromosomes that are paired are homologous to each other.

Sex-Determining Chromosomes

Two of the chromosomes in the human genome are sex chromosomes.

• Females: two X chromosomes (XX)

• Males: one X chromosome and one Y chromosome (XY)

• More than 1400 genes are found on the human X chromosome, whereas the human Y chromosome contains only about 158 genes.