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The generation of special crosses between different inbred lines such as recombinant inbred strains (RIS) and intermated recombinant inbred populations (IRIP) is being used to improve the power of QTL detection techniques, in particular fine mapping. These approaches acknowledge the fact that recombination of linked loci increases with every generation, caused by the accumulation of crossovers appearing between the loci at each meiosis. This leads to an expansion of the map distance between the loci. While the amount of the map expansion of RIS and IRIP is known for infinite inbred generations, it is not known for finite numbers of generations. This gap was closed here. Since the recursive evaluation of the map expansion factors turned out to be complex, a useful approximation was derived.

Functional melanocytes in the epidermis are required for cutaneous pigmentation in cattle. In spotted cattle variations in the size of pigmented sectors are of interest to animal researchers, as it is believed that those with a higher proportion of white coat absorb less solar radiation. The proportion of unpigmented coat was determined from photographs of German Simmental and Holstein bulls. The receptor tyrosinase kinase (KIT) locus is associated with depigmentation phenotypes in mice, humans and pigs, and it is suggested that KIT is a candidate gene for the degree of spotting in cattle.

Develops a model allowing parallel nonsister strand chiasmata, which could not arise under high suppression interference if one assumes suppression on all strands and sister strand chiasmata. Components of interference; Example of a four-strand-stage meiosis with four chiasmata and resulting gametes; Chiasmata's assistance in the organization of meiosis by fixing strands.