Linkage and Mapping in Eukaryotes

These flashcards cover key terms and concepts related to linkage and mapping in eukaryotes, particularly in Drosophila, providing definitions for better understanding.

Linkage

The tendency of genes located close together on a chromosome to be inherited together.

Recombination

The process by which genetic material is rearranged during meiosis, resulting in new combinations of alleles.

Chiasma

The point at which paired chromosomes are attached during crossing over in meiosis.

Testcross

A cross between an individual of unknown genotype and a homozygous recessive individual to determine the unknown genotype.

Map unit (mu)

A unit of measurement for genetic distance; 1 mu corresponds to a 1% recombination frequency.

Cis-configuration

An arrangement where one chromosome carries two mutations and the homolog carries both wild-type alleles.

Trans-configuration

An arrangement where the two mutations are on separate homologs, as are the wild-type alleles.

Nonparental phenotype

Offspring phenotypes that differ from the parental generation, resulting from recombination.

Phenotypic ratio

The ratio of different phenotypes produced in a genetic cross.

Independent assortment

The principle that alleles for different traits are distributed to sex cells (&later offspring) independently of one another.

Crossing over

The exchange of genetic material between homologous chromosomes during meiosis, leading to recombination.

Recombinant gametes

Gametes that carry combinations of alleles that are different from those found in the parents.

Centimorgan (cM)

A unit of measure for genetic linkage; represents a 1% chance that a crossover will occur between two genes.

Drosophila

A genus of small flies, commonly known as fruit flies, used as a model organism in genetics.