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Human Genetics: When Things Go Awry!. Nondisjunction Karyotyping Chromosomal Mutations. Meiosis I and II. Normal Human Karyotype. Normal Male Karyotype. Karyotype. An orderly display of magnified images of an individual’s chromosome
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Human Genetics: When Things Go Awry! Nondisjunction Karyotyping Chromosomal Mutations
Karyotype • An orderly display of magnified images of an individual’s chromosome • Appear in metaphase: thick and doubled (with their sister) • See procedure for making karyotype from blood sample (in textbook or in handout)
Nondisjunction • An accident of meiosis (or mitosis) in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase • May result in an abnormal chromosome number in either sex • May result in abnormal number of autosomal chromosomes • May result in abnormal number of sex chromosomes
Chromosomal Mutations • Changes in the number or structure of chromosomes • May change location of certain genes on chromosomes • May change the number of copies of genes • Include: • Deletions • Duplications • Inversions • Translocations • When would such events occur during meiosis?