This review on the coat colour and texture of dogs deals, locus by locus, with the control of colour, modification of basic patterns, white spotting, and single-gene effects on hair structure.

A frequency of more than 10(-2) of the de novo appearance of piebald spotting (star) was established in silver-black foxes selected for domestic behavior. The star phenotype is determined by the autosomal semidominant gene S. Ten genealogical groups of foxes, in which star arose independently, were analyzed. Of these, the star character is determined by S alleles in at least seven groups. The S gene is located in a linkage group other than the earlier described W (Georgian white) locus. The star gene is incompletely penetrant, but its penetrance is significantly higher in offspring from tame mothers than from aggressive ones, or when S is received from a heterozygous vixen (Ss). There was a notable shortage of homozygous (SS) offspring from Ss X Ss crosses, which cannot be adequately explained by selective embryonic mortality, differential zygotic and gametic death, or transgression of homozygous and heterozygous phenotypes. Some foxes, proven carriers of a homozygous (Ss) genotype, showed the phenotype and mode of inheritance characteristic of heterozygotes (Ss). Presumably, the mechanism responsible of these observations is a heritable functional activation-inactivation of the star gene. Some implications of this concept in terms of destabilizing selection are discussed.

SummaryChromosome 1 with one or two long insertions has been previously found in natural mouse populations. The inheritance of chromosome 1 with two insertions from the Yakutsk population is analysed in this paper. It was demonstrated that heterozygous females transmit this chromosome to 80–85% of offspring. The observations made at M II, in conjunction with the recombination data, allowed us to conclude that preferential passage of the chromosome 1 with insertions to the oocyte and egg, rather than to the first and second polar bodies at meiosis, is the causative factor of the distorted segregation. A meiotic drive of such potency has not been previously reported for female mammals. The possible mechanism of the drive is discussed.

The principles and the organization of current genetic improvement programmes, breeding objectives, selection criteria, economic and non-economic traits, breeding value, the design of breeding programmes, genetic gain and the usefulness of genetic markers and genomic selection in pig breeding are discussed.

This chapter discusses classical and molecular cytogenetics, chromosome analysis, karyotypes and gene mapping in pigs.