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Human Chromosomes
How many chromosomes do humans have?• 46
• In 23 pairs – one in each pair from mom, one from dad
• Matched pair = homologous chromosomesThey have the same genes in the same order
(but not necessarily the same alleles)
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.
Homologous Chromosomes
Eye color locus
Hitchhiker thumb locus
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
Humans have 23 Sets of Homologous ChromosomesEach Homologous set is made up of 2 Homologues.
Homologue
Homologue
Autosomes(The Autosomes code for most of the offspring’s traits)
In Humans the “Autosomes” are sets 1 - 22
Sex Chromosomes
Sex ChromosomesThe 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 - female XY chromosome - male
In Humans the “Sex
Chromosomes” are the 23rd set
X chromosome Y chromosome