Inactive myostatin (one or two copies) results in increased muscularity, increased yield of closely trimmed retail product, reduced fat content, increased lean growth efficiency, reduced quality grade, increased birth weight, and increased dystocia. Even though one or two copies of inactive myostatin reduces quality grade or marbling compared to zero copies, there is no decrease in meat tendern...

The male part of fertility traits in pigs has not often been analysed because of missing semen quality data in the case of natural mating. With increasing AI in pigs more data about semen quality of boars is available, so its influence on litter size can be analysed on bigger data sets. With advanced recording systems, single matings are recorded and important economic traits like mating succes...

Recent studies of wild tamarins and marmosets have shown that at least one species exhibits variable mating patterns, including cooperative polyandry, monogamy and, more rarely, polygyny. Polyandry is thought to occur because the high frequency of twinning and the relatively high weights of infants in these species make the rearing of infants unusually difficult. Nonreproductive helpers (older ...

TABLE OF CONTENTS INTRODUCTION. .................................................................. 167 Systems of breeding.. ................................ ~. ........................... 167 Parental and fraternal correlations.. ............................................... 169 Homozygosis.. ................................................................... 171 The percentage of homozygosi...

Introduction The yeast two-hybrid system is a powerful assay for protein-protein interactions 1. As described elsewhere in this volume, several versions of the twohybrid system have been developed. Most versions have the following features. The two proteins to be tested for interaction are expressed as hybrids in the nucleus of a yeast cell. One of the proteins is fused to the DNA binding domai...

Recently, models of sympatric speciation have suggested that assortative mating can develop between sympatric morphs due to divergence in an ecologically important character. For example, in sympatric pairs of threespine stickleback (Gasterosteus aculeatus L.) size-assortative mating seems to be instrumental in reproductive isolation. Here, we examine courtship behaviour and assortative mating ...

Interactions with parasites may promote the evolution of disassortative mating in host populations as a mechanism through which genetically diverse offspring can be produced. This possibility has been confirmed through simulation studies and suggested for some empirical systems in which disassortative mating by disease resistance genotype has been documented. The generality of this phenomenon i...

Sexually transmitted infections (STIs) are often associated with chronic diseases and can have severe impacts on host reproductive success. For airborne or socially transmitted pathogens, patterns of contact by which the infection spreads tend to be dispersed and each contact may be of very short duration. By contrast, the transmission pathways for STIs are usually characterized by repeated con...

A class of multilocus models that incorporate both preferential mating and viability selection is studied. Symmetry in alleles is supposed, resulting in the phenotypes being dependent only on the location of heterozygous loci. Otherwise, an arbitrary number of loci, number of alleles per locus, and arbitrary recombination schemes, viability parameters, and preferential mating pattern are allowe...