BIOSC-101 Chapter Notes - Chapter 1: Homologous Chromosome, Down Syndrome, Nondisjunction
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31 Aug 2020
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Genetic and phenotypical changes occur when there are breaks or changes to the. Dna or losses of one or more chromosomes of an organism. The four types of chromosomal alterations for breakages are. A deletion is when a broken segment is lost from a chromosome. Occurs when the gametes that fertilize possess a deletion in at least one of their chromosomes. A duplication is when a broken segment from one chromosome is duplicated on its homologous chromosome. A translocation is when a broken segment is attached to a nonhomologous. Occurs during recombination where the two chromosomes involved chromosome don"t contain the same genes. An inversion is when a broken segment reattaches to the same chromosome it left but so that the gene is in a reversed order. Nondisjunction is the failure of homologous pairs to separate after meiosis i. Misdivision is the failure of chromatids to separate after meiosis ii.