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Biology Chapter 12.1
Biology Chapter 12.1 Terms and Definitions
| Term | Definition |
|---|---|
| sex chromosomes | one of the pair of chromosomes that determine the sex of an individual |
| autosome | any chromosome that is not a sex chromosome |
| sex-linked trait | an autosomal trait that is influenced by the presence of male or female sex hormones |
| linked gene | one of a pair of genes that tend to be inherited together |
| chromosome map | a diagram of gene positions on a chromosome |
| map unit | in chromosome mapping, an increment of 1 percent in the frequency of crossing-over |
| germ cell mutation | mutation occurring in gametes |
| somatic cell mutation | a mutation that occurs in a body cell |
| lethal mutation | a mutation that affects the organism so much that it can't survive |
| deletion | the loss of a part of DNA from a chromosome |
| inversion | a reversal in the order of the genes, or of a chromosome segment within a chromosome |
| translocation | the movement of a segment of DNA from one chromosome to another, which results in a change in the position of the segment |
| nondisjunction | the failure of homologous chromosomes to separate during meiosis 1 or the failure of sister chromatids to separate during mitosis or meiosis II |
| point mutation | a mutation in which only one nucleotide or nitrogenous base in a gene is changed |
| substitution | a mutation in which one nucleotide is replaced by another nucleotide |
| frameshift mutation | a mutation, such as the insertion or deletion of a nucleotide in a coding sequence that results in the misreading of the code during translation because of a change in the reading frame |
| insertion mutation | a mutation in which one or more nucleotides are added to a gene |