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 |