Chapter 12- Vocabulary Flashcards
(31 cards)
Autosomes
The remaining chromosomes that are not directly involved in determining the sex of an individual
Sex chromosome
Contain genes that determine the sex ( gender) of an individual
Sex-linked trait
Refers to a trait that is coded for by an allele on a sex chromosome
Linked genes
Pairs of genes that tend to be inherited together
Chromosome map
A diagram that shows the linear order of genes on a chromosome
Map unit
A frequency of crossing over of 1 percent
Germ cell mutations
Occur in an organisms gametes
Somatic cell mutations
Take place on an organisms body cells and can therefore affect the organism
Lethal mutations
Cause death
Deletion
The loss of a piece of a chromosome due to breakage
Inversion
A chromosomal segment breaks off, flips around backward, and reattaches
Translocation
A piece of one chromosome breaks off and reattaches to a nonhomologous chromosome
Nondisjunction
A chromosome fails to separate from its homologue during meiosis
Point mutation
Addition or removal of a single nucleotide
Substitution
One nucleotide replaces another
Frameshift mutation
When a loss of one or more nucleotides in a gene causes incorrect grouping of the remaining codons
Insertion mutations
One or more nucleotides are added to a gene
Pedigree
A diagram that shows how a trait is inherited over several generations
Carrier
Has one copy of the recessive allele but do not have the disease
Genetic disorders
Diseases or disabling conditions that have a genetic basis
Polygenic
Influenced by several genes
Complex characters
Characters that are influenced strongly both by the environment and by genes
Multiple allele
Genes with three or more alleles
Codominence
Both alleles are expressed in the phenotype of a heterozygote