The effect of linkage on the additive by additive covariance between relatives

• Published in: Genetics selection evolution (Paris) 1998-10, Vol.30 (5), p.409-421
• Main Authors: TOTIR, L. R, FERNANDO, R. L
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Classical genetics, quantitative genetics, hybrids; Fundamental and applied biological sciences. Psychology; Genetics of eukaryotes. Biological and molecular evolution; Methods, theories and miscellaneous
• ISSN: 0999-193X; 1297-9686
• DOI: 10.1051/gse:19980501

The additive x additive relationship coefficient needs to be calculated in order to compute genetic covariance between relatives. For linked loci, the computation of this coefficient is not as simple as for unlinked loci. Recursive formulae are given to compute the additive x additive relationship coefficient for an arbitrary pedigree. Based on the recursive formulae, numerical values of the desired coefficient for selfed or outbred individuals are examined. The method presented provides the means to compute the additive x additive relationship coefficient for any situation assuming linkage. The effect of linkage on the covariance was examined for several pairs of relatives. In the absence of inbreeding, linkage has no effect on the parent-offspring covariance. All of the other relationships examined were affected by linkage. As recombination rate increased from 0.1 to 0.5, in descending order of percentage change in the covariance, the relationships ranked as follows: first cousins, double first cousins, grandparent-grandoffspring, half sibs, aunt-nephew, full sibs, parent-offspring. With inbreeding, the parent-offspring covariance is also affected by linkage.