Linked genes and Gene Mapping

Linked Genes

Genes that tend to be inherited together and are located near each other on the same chromosome.

Genetic Recombination

Production of offspring with combinations of traits that differ from those found in either parent due to crossing over.

Parental Types

The original gene combinations present in the parents, represented as AB or ab.

Recombinants

Genetic combinations that do not match either parent, such as Ab or aB.

Recombinant Frequency

The proportion of offspring that are recombinants, calculated by crossing heterozygous parents with a homozygous recessive individual.

Map Units

A unit of measurement that represents the distance between genes on a chromosome; 1% recombination equals 1 map unit.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis that leads to genetic recombination.

Independent Assortment

The normal Mendelian inheritance pattern where genes segregate independently during gamete formation.

Maximum Value of Recombination

A limit of 50% for genes that are so far apart that crossing over is virtually certain, indicating genetic unlinked status.

Linkage Maps

Maps that depict the order of genes on a chromosome, but do not provide precise locations.

Recombine

To form new combinations of genes in offspring that differ from those in the parents.

Gene

A segment of DNA that contains instructions for the synthesis of proteins and can influence traits.

Homozygous Recessive

An individual with two identical recessive alleles for a trait.

Heterozygous

An individual with two different alleles for a trait.

Chromosome

A structure that consists of DNA and proteins, carrying genetic information.

Deviation from Normal Inheritance

When the results of genetic crosses do not follow typical patterns due to linked genes.

Offspring

The product of reproduction, which can inherit genes from both parents.

Trait

A characteristic or feature of an organism that can be inherited.

Allele

Different forms of a gene that may govern a particular trait.

AB Type

An individual that carries the dominant alleles for both traits from linked genes.

ab Type

An individual that carries the recessive alleles for both traits from linked genes.

Ab Type

An individual that carries a dominant allele for the first trait and a recessive allele for the second trait.

aB Type

An individual that carries a recessive allele for the first trait and a dominant allele for the second trait.

Distance Traits

The relative spacing of genes on a chromosome, measured in map units.

Genetic Linkage

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

Cross

The mating of two organisms to analyze the inheritance of traits.

F1 Generation

The first generation of offspring from a genetic cross.

Genetically Unlinked

Genes that assort independently, resulting in no linkage observed.

Precision of Linkage Maps

Linkage maps provide the order of genes, but not their exact location.

Crossover Frequency

The frequency at which alleles on chromosomes are separated due to crossing over.

Genetic Traits

Characteristics of an organism that are influenced by genes.