Fish Genetics: Inbreeding and Outbreeding

The mating of closely related individuals, increasing the chance of offspring inheriting two identical copies of a gene.

The mating of unrelated individuals, increasing genetic diversity and reducing the chances of offspring inheriting harmful recessive genes.

A measure of how homozygous an individual is compared to the population average, calculated based on the relationship between parents.

Reduction in fitness due to inbreeding, resulting in lower survival rates, reduced fertility, and increased susceptibility to diseases.

The process of analyzing the ancestry of individuals to determine the degree of relatedness and potential for inbreeding.

The state of having two identical copies of a gene, one from each parent.

The state of having two different copies of a gene, one from each parent.

Loss of genetic variation within a population, making it more vulnerable to environmental changes and diseases.

The decrease in genetic variety within a population, leading to greater susceptibility to diseases, infertility, and other issues.

The process of identifying close relatives within a fish population using a pedigree chart (family tree).

A system that uses identification tags or markings to track individual fish in a population, allowing for identification of specific individuals and their genetic lineage.

The process of removing fish with poor physical characteristics (constitution) from breeding programs to improve overall population health.

The process of breeding individuals that are closely related, increasing the frequency of homozygous alleles and leading to potential harmful effects like reduced fertility and increased disease susceptibility.

Harmful recessive genes, usually masked when paired with a dominant allele, are expressed in individuals carrying two copies of the recessive allele. This leads to genetic disorders.

Utilizing inbreeding to establish genetically uniform populations for research purposes, aiding in the study of specific traits.

The regular replacement of breeding stock in a hatchery to prevent excessive inbreeding.

Mixing brood stocks of varying ages to prevent genetic drift and loss of valuable alleles.

Introducing individuals from natural populations into a hatchery to increase genetic diversity.

Maintaining a detailed history of breeding stock to prevent mating between closely related individuals.

Inbreeding is the mating of individuals who are more closely related than the average individuals in the population. This increases the probability of offspring inheriting two copies of the same allele (homozygosity).

Inbreeding depression refers to the reduced fitness of a population due to increased homozygosity. This can be caused by the expression of harmful recessive alleles, which are more likely to combine when individuals are closely related.

Gene flow is the transfer of genetic material between populations. It occurs when individuals from different populations interbreed, introducing new alleles and increasing genetic diversity.

Gene flow can reduce inbreeding by introducing new alleles. This helps to avoid the accumulation of harmful recessive alleles, which are often expressed due to close mating.

Inbreeding can be deliberately used in breeding programs to create genetically homogeneous populations with desired characteristics. This is often used in livestock and agriculture to maintain certain traits.

Outbreeding is the mating of individuals who are less closely related than the average individuals in the population. It is often used to increase genetic diversity and introduce new traits into a population.

Outbreeding depression can occur when individuals from very different populations interbreed. The offspring may have reduced fitness due to a mismatch of genes or adaptations to different environments.

The coefficient of inbreeding (F) measures the probability that two alleles at a locus are identical by descent. It provides a quantitative measure of the level of inbreeding within an individual or population.