Kapitel 19 Flashcards
An alternative form of a gene; for a given gene - many alleles may exist in the gene pool of the species.
allele
Mode of reproduction in which offspring arise from a single parent - producing an individual genetically identical to that parent; includes budding - binary fission - and parthenogenesis.
asexual reproduction
Structure formed when a duplicated chromosome pairs with its homolog at the beginning of meiosis; contains four sister chromatids.
bivalent
X-shaped connection between paired homologous chromosomes during meiosis; represents a site of crossing-over between two non-sister chromatids.
chiasma (plural chiasmata)
Experimental techniques used to isolate the genes responsible for an interesting phenotype.
classical genetic approach
Genetic experiment that determines whether two mutations that are associated with the same phenotype lie in the same gene or in different genes.
complementation test
Process whereby two homologous chromosomes break at corresponding sites and rejoin to produce two recombined chromosomes that have physically exchanged segments of DNA.
crossing-over
Describes a cell or organism containing two sets of homologous chromosomes - one inherited from each parent. (See alsohaploid.)
diploid
The fusion of two gametes—sperm and egg—to produce a new individual organism.
fertilization
Genetic change that increases the activity of a gene or makes it active in inappropriate circumstances; such mutations are usually dominant.
gain-of-function mutation
Cell type in a diploid organism that carries only one set of chromosomes and is specialized for sexual reproduction. A sperm or an egg; also called germ cell.
gamete
A graphic representation of the order of genes in chromosomes spaced according to the amount of recombination that occurs between them.
genetic map
Experimental technique used to search through a collection of mutants for a particular phenotype.
genetic screen
The study of genes - heredity - and the variation that gives rise to differences between one living organism and another.
genetics
The genetic makeup of a cell or organism - including which alleles (gene variants) it carries.
genotype