• Diploid set for humans; 2n = 46
• Autosomes; homologous chromosomes, one from each parent (humans = 22 sets of 2)
• Sex chromosomes (humans have 1 set)
  1. Female-sex chromosomes are homologous (XX)
  2. Male-sex chromosomes are non-homologous (XY)

Karyotype

• A pictorial display of metaphase chromosomes from a mitotic cell
• Homologous chromosomes- pairs

Spectral Karyotyping- a new method

Ploidy: Number of sets of chromosomes in a cell

• Haploid (n)-- one set chromosomes
• Diploid (2n)-- two sets chromosomes
• Most plant and animal adults are diploid (2n)
• Eggs and sperm are haploid (n)