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Terms 12.1
Term | Definition |
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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 determined by a gene found on one of the sex chromosomes, such as the X chromosome or the Y chromosome in humans |
linked genes | one 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% in the frecquency 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 can't survive |
deletion | the loss of DNA from a chromosome |
inversion | a reverse in the order of the genes, or 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 2 |
point mutation | a mutation in which only one nucleotide or nitrogenous base in a gene is changed |
substitution | a mutation in which a nucleotide or a codon in DN is replaced with a different 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 the change in the reading frame |
insertion mutation | a mutation in which one or more nucleotides are added to a gene |