Linkage and Genetic Mapping in Eukaryotes

Flashcards about Linkage and Genetic Mapping in Eukaryotes

Creighton and McClintock

Crossing over may produce new combinations of alleles and resulted in the exchange of segments between homologous chromosomes.

Genetic mapping

The frequency of recombination between two genes can be correlated with their map distance along a chromosomes.

Linkage

Two genes that are located on the same chromosome.

Linked Genes

Genes that are close together tend to be transmitted from parent to offspring as a group.

Linkage groups

Genes on a chromosome are physically connected to one another.

Crossing Over

Crossing over may alter the linkage of genes.

Nonparental or recombinant cells

Contain the new allelic combinations.

Parental cells

Contain the original combination of alleles

Bateson and Punnett

Not all traits assort independently.

Morgan

The linkage of X-Linked genes and proposed that crossing over between X chromosomes can occur.

Null hypothesis

The traits are assorting independently assumed no real difference between observed and expected values.

They worked with corn as an experimental sample.Creighton and McClintock

Responsible for providing the first direct evidence that crossing over is associated with genetic recombination.

Mitotic recombination

Crossing over during mitosis may produce a pair of recombinant chromosomes that have a new combination of alleles.

Twin spots

Adjacent areas of the body in Drosophila may express different alleles for bristle length and body color. Twin spots are the result of mitotic recombination.

Genetic mapping

Determines the linear order and distance of genes on a chromosome

Genetic linkage map

The linear order of genes on the chromosome

Recombinant offspring

Have different combinations of alleles than either of the parental strains.

Nonrecombinant offspring

Have the same combinations of alleles as one of the parental strains.

Map distance

The number recombinant offspring divided by the total number of offspring, multiplied by hundred.

Alfred Sturtevant

Used Drosophila melanogaster as the model system to construct the first genetic map.