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Vocab 12.1
Terms for chapter 12 section 1
| Question | Answer |
|---|---|
| sex chromosome | 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 | a trait that is influenced by the presence of male or female sex hormones |
| sex-linked gene | a trait that is determined by a gene found on one of the sex chromosomes, such as the X chromosome or the Y chromosome in humans |
| 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 that occurs in an organism's gametes |
| somatic-cell mutation | a mutation that occurs in a body cell |
| lethal mutation | a gene or chromosomal mutation that influences the development of an organism in such a way that the organism cannot 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; also the movement of soluble nutrients from one part of a plant to the other |
| nondisjunction | the failure of the homologous chromosomes to separate during meiosis 1 or the failure of the sister chromatids to separate during mitosis or meiosis 2 |
| point mutation | a mutation in which only one nucleotide or nitrogenous base in a gene is charged |
| substitution | a mutation in which a nucleotide or a codon in DNA is replaced with a different nucleotide |
| frameshift mutation | a mutation, such as the insertion or deletion of a nucleotide in the 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 |