Inbreeding

Inbreeding. Prepared by Siddik, Göttingen universität.

1. Inbreeding Definition : Inbreeding means mating between individuals that are related to each other by ancestry ( Falconer, quantitative genetics ). It‘s very common in small population. Impact : Inbreeding increases the proportion of homozygosity which enhance the chances of offspring being affected by recessive or deleterious traits . It creates lot of genetic disorder like haemophilia, cysic fibrosis, sickle cell anemia and so on It is totally opposite to outbreeding. Basically used in selective breedind like livestock – to eastablish new desirable trait in the stock. In livestock: Reduction of Litter size and fertility. Positive: Fastest racing dogs Comes from homozygosity. Common fruits female flies prefer mates with her own brothers.

2. Inbreeding in a diagram www.iflscience.com/plants-and-animals/how-serious-inbreeding-show-dogs/ Affected by deleterious allele

3. Inbreeding Depression Experiment : Sweden #Adders: 40 (Vipera berus). Impact : Stillborn and deformed offspring Fig : Vipera berus http://evolution.berkeley.edu/evolibrary/article/conservation_03

4. Inbreeding Depression Definition : The reduction of survival and fertility rate of inbred offspring. It occurs both plant and animal population as well as human . the harmful effect of inbreeding depression first observed by Charls Darwin, in 57 plant species where self fertilization occurs between the individuals. Inbreeding coeeficient Definition: way of measurement of inbreeding depression. Formula: F= (He – Ho) / He [if, inbreeding is only souce of diseuilibrium] Here, F = Inbreeding coefficient, H e = Expected Heterozygosity, H e = Observed Heterozygosity Interpretation: F = , no inbreeding F= 1 , complete inbreeding Low F means less inbreeding High F means significant inbreeding

5. Relationship between Kinship and inbreeding coefficient Identity by State(ibs): if the two alleles are functionally same. Identity by descent(ibd): Two alleles are ibd if one is direct physical copy of other, or both of two are physical copies of the same ancestral allele. Kinship coefficient ( Φ ij ) : In between two individuals i and j, it is just probability that one allele randomly selected from i and other allele is randomly selected from the same autosomal locus of j, which are ibd. Formula: Here, k and l are the parents of individual i, f = inbreeding coefficient

6. References : https://en.wikipedia.org/wiki/Inbreeding#/media/File:Fruit_flies.jpg http://www.iflscience.com/plants-and-animals/how-serious-inbreeding-show-dogs/ http://evolution.berkeley.edu/evolibrary/article/conservation_03