Quantifying the importance of random genetic drift in natural populations is central to understanding the potential limits to natural selection. One approach is to estimate the magnitude of heterosis, the increased fitness of progeny derived from crosses between populations relative to crosses within populations caused by the heterozygous masking of deleterious recessive or nearly recessive all...

The advancement in microarray technology enables the simultaneous measurement of expression levels of thousands of genes. However, due to the relatively high cost of making a replicate in a microarray experiment, the number of replicates in a single experiment is typically small. This results in the “small n, large p” problem for statistical inferences, where there are gene expression measureme...

This study was conducted to produce a high percentage of genetically male tilapia through interspecific hybridization between Nile tilapia, Oreochromis niloticus and Blue tilapia, O. aureus and evaluate sex ratio, productive performance and heterosis of the progeny produced. The results revealed that sex ratios of the progenies of (♀ O. aureus x ♂ O. niloticus) and (♀ O. niloticus x ♂ O. aureus...

The primary objective was to estimate breed, heterosis, and recombination effects on growth and carcass traits of two different four-breed composite populations of pigs. Experiment 1 (Exp. 1) included purebred and crossbred pigs originating from Yorkshire, Landrace, Large White, and Chester White breeds, and Experiment 2 (Exp. 2) included pigs from Duroc, Hampshire, Pietrain, and Spot breeds. D...

This study was conducted to produce a high percentage of genetically male tilapia through interspecific hybridization between Nile tilapia, Oreochromis niloticus and Blue tilapia, O. aureus and evaluate sex ratio, productive performance and heterosis of the progeny produced. The results revealed that sex ratios of the progenies of (♀ O. aureus x ♂ O. niloticus) and (♀ O. niloticus x ♂ O. aureus...

Reciprocal cross effects (i.e., differences between reciprocal hybrids that are developed by reversing the strains from which the dam and the sire are taken) are commonly used as a measure of sex-linkage or maternal effects. Morphometric traits were studied in a cross between two geographic populations of Drosophila kikkawai, i.e. a northern and southern. Average values in the F1 was similar an...

Embryo transfers were used to demonstrate that the genotype of the mother providing the uterine developmental environment significantly influences postnatal growth and adult body size of her progeny. Irrespective of their own genotype, mouse embryos transferred into the uterus of an inbred strain with large body size (C3H) had greater body weights, longer tails and higher growth rates than thos...

By using both numerical and analytical approaches, we have shown that heterosis alone is not a mechanism for maintaining many alleles segregating at a locus. Even when all heterozygous are more fit than all homozygotes, the proportion of fitness arrays that will lead to a stable, feasible equilibrium of more than 6 or 7 alleles is vanishingly small. More alleles can be maintained if, in additio...