BIOL 1107 Chapter Notes - Chapter 13: Sister Chromatids, Meiosis, Allosome
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Meiosis leads to offspring that are genetically distinct from each other and their parents. Leading hypothesis to explain meiosis is that genetically variable offspring are more likely to thrive in environments where parasites and disease are common. If mistakes occur during meiosis, resulting egg and sperm may contain wrong number of chromosomes: rare for offspring with incorrect number of chromosomes to develop normally. During sexual reproduction, a sperm and egg unite to form a new individual-fertilization. Each organism has a characteristic number of chromosomes. Karyotype-number and types of chromosomes present in an organism. Human have 46 chromosomes in every cell except gametes: 1 pair of sex chromosomes, 22 pairs of autosomes. Homologous chromosomes or homologs-chromosomes of the same type. Chromosomes carry a gene, gene-section of dna that influences one or more hereditary traits in an individual: different versions of a specific gene are called alleles.