Inbreeding & Diversity
Overview
Inbreeding occurs when closely related animals are mated with each other.
Depending on how closely related the parents are, the probability increases that offspring will inherit identical gene segments from both parents. This can be used to consolidate desired traits, but inevitably always leads to a reduction in genetic diversity.
The lower this diversity, the lower the adaptability (fitness) to environmental changes (at the population level) and the higher the risk of hereditary diseases, reduced fertility and lower resistance to disease.
A genome analysis at Generatio allows the actual extent of inbreeding and diversity to be accurately assessed (analysis by animal species)
The findings help to better assess non-specific diseases in individual animals and are a valuable tool in breeding for targeted mating planning. Consistent, long-term application of genome findings is the method of choice for building robust lines and counteracting the risk of inbreeding depression.
Genomic Analysis for Inbreeding and Diversity
For ‘Inbreeding and Diversity’ testing, the animal's DNA is preferably examined using so-called SNP arrays (‘SNP chips’). These ‘chips’ contain tens of thousands of genetic markers. The distance between the individual markers in the genome determines the resolution power of the SNP chip used. The closer the markers are located to each other, the better the resolution and the more reliably the entire genome is represented.
The right chip is determined by the animal species being examined and the respective average degree of inbreeding. See: Analysis by animal species
Parts of the Analysis
Localisation of Inbreeding by ROH
DNA segments that are identical as a result of inbreeding appear as extended regions (RUNs) of homozygosity.
Details can be found in the corresponding lexicon entry: ROH
and in our example pages: ROH and ROH profiles.
Extent of Inbreeding (GIC)
The genomic inbreeding coefficient (GIC) is calculated from the sum of all ROH segments.
Details can be found in the corresponding encyclopaedia entry: GIK
and at: Genomic inbreeding coefficient
Calculation of Heterozygosity (HE)
The genomic heterozygosity value (HE) is a measure of the genetic diversity/fitness present in the animal being examined.
Details can be found in the corresponding lexicon entry: Link to HE
and at: Genomic Heterozygosity
Only examinations that cover all three parts described above can be used for scientifically based mating evaluations to avoid inbreeding and for the complete characterisation of an animal's actual inbreeding status.