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Mistakes in Meiosis. Nondisjunction. The failure of homologous chromosomes to separate properly during meiosis. Nondisjuction. Trisomy – extra chromosome (has 47) Ex: Down syndrome is Trisomy 21 Monosomy – missing a chromosme Usually does not survive (has 45). Triploid.
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Nondisjunction • The failure of homologous chromosomes to separate properly during meiosis.
Nondisjuction • Trisomy – extra chromosome (has 47) • Ex: Down syndrome is Trisomy 21 • Monosomy – missing a chromosme • Usually does not survive (has 45)
Triploid • Has 3 sets of chromosomes • One gamete has 2 copies (diploid) and is fertilized by a gamete with the normal one copy (haploid)
Tetraploid • Has 4 sets of chromosomes • Both gametes have 2 copies (diploid) of each chromosome • Usually causes death in animals • Causes larger and healthier flowers and plants