Heterosis, or hybrid vigor, refers to the phenomenon in which hybrid progeny of two inbred varieties exhibits enhanced growth or agronomic performance. Although a century-long history of research has generated several hypotheses regarding the genetic basis of heterosis, the molecular mechanisms underlying heterosis and heterotic gene expression remain elusive. Here, we report a genome-wide gene...

The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widely reported over the past 25 years. A large load of deleterious recessive mutations could explain ...

Although most discussions today start from the assumption that the secular rise in IQ must be environmental in origin, three reasons warrant giving the genetic phenomenon heterosis a closer look as a potential cause. First, it easily accounts for both the high heritability and low shared environmental effects seen in IQ, findings that are difficult to reconcile with environmental hypotheses. Se...

Identifying intra-locus interactions underlying heterotic variation among whole-genome hybrids is a key to understanding mechanisms of heterosis and exploiting it for crop and livestock improvement. In this study, we present the development and first use of the heterotic trait locus (HTL) mapping approach to associate specific intra-locus interactions with an overdominant heterotic mode of inhe...

Heterosis has been widely exploited as an approach to enhance crop traits during breeding. However, its underlying molecular genetic mechanisms remain unclear. Recent advances in RNA sequencing technology (RNA-seq) have provided an opportunity to conduct transcriptome profiling for heterosis studies. We used RNA-seq to analyze the flower transcriptomes of two F1 hybrid soybeans (HYBSOY-1 and HY...

Jiyan-1 puffer, the F1 hybrid of Takifugu rubripes and Takifugu flavidus, displays obvious heterosis in the growth performance, flavor and stress tolerance. In the present study, comparative analysis for the transcriptomes of T. rubripes, T. flavidus and Jiyan-1 was performed aiming to reveal the possible mechanisms of heterosis in pufferfish. Whole transcriptomes were sequenced using the SOLiD...

Understanding how parental distance affects offspring fitness, i.e., the effects of inbreeding and outbreeding in natural populations, is a major goal in evolutionary biology. While inbreeding is often associated with fitness reduction (inbreeding depression), interpopulation outcrossing may have either positive (heterosis) or negative (outbreeding depression) effects. Within a metapopulation, ...

DNA methylation is an important regulatory mechanism for gene expression that involved in the biological processes of development and differentiation in plants. To investigate the association of DNA methylation with heterosis in Brassica, a set of intraspecific hybrids in Brassica rapa and B. napus and interspecific hybrids between B. rapa and B. napus, together with parental lines, were used t...

Heterosis and combining ability for total number of eggs laid per female silkworm Bombyx mori L were investigated in a six parent diallel crossing programme in four rearing seasons. Magnitude of heterosis varied from seasons to season and was not consistent over characters. Effect of season was important in the expression of genetic variances and other parameters studied. Considerable amount to...