Wednesday, January 13, 2016

Some clear mechanisms for epigenetic inheritance further strengthen Denis Noble's view

From Fig 1 of Chen et al. Scatter plot of
HFD vs ND comparison for sperm tsRNAs and miRNAs.
Two rather stunning papers in Science demonstrate mechanisms of epigenetic inheritance that further strengthen the (Denis) Noble view and demolish Dawkins' simplistic gene-centered nonsense.

Chen at al show that in a paternal high-fat diet (HFD) mouse model, a subset of sperm tRNA-derived small RNAs (tsRNAs) exhibit changes in expression profiles and RNA modifications. Injection of sperm tsRNA fractions from HFD male into normal zygotes generated metabolic disorders in the F1 offspring and altered gene expression of metabolic pathways in early embryos and islets of F1 offspring, which was unrelated to DNA methylation at CpG-enriched regions. Hence, sperm tsRNAs represent a type of paternal epigenetic factor that may mediate intergenerational inheritance of diet-induced metabolic disorder.

Meanwhile Sharma et al shed some important light on how these tRNA fragments mature in the testes.

The important point is that these are clear mechanisms for epigentic inheritance - and there will be others. As ususal, Noble is right and Dawkins' simplistic "selfish gene" stuff is shown to be ... oversimplistic nonsense.

PS Denis is organising a major 3-day conference at The Royal Society in Novemeber "New trends in evolutionary biology: biological, philosophical and social science perspectives."  Alas I fear I won't have time to attend it all but it will be fascinating.



Another aspect of non-genetic inheritance is of course the Microbiome and Sonnenberg et al in this week’s Nature give some further insights into this.
 

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