Lactose tolerance is regulated by epigenetic factors

Methylation at the LCT promoter and enhancer is highly predictive of lactase enzymatic activity

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5884863/

Excerpts: "On the other hand, although it is generally accepted that there is a strong association between the ancestral -13910*C allele with lactase non-persistence and the variant -13910*T allele with lactase persistence in people of European descent, in some cases these genotypes are not completely predictive of the phenotype. Yet, the physiological change in lactase gene expression occurs in the context of a stable DNA sequence. This suggests the presence of dynamic mediators of LCT regulation such as epigenetic modifications and/or transcriptional changes."

"DNA methylation also plays an important role in regulation of human LCT. This was confirmed by Labrie et al. who identified epigenetically controlled regulatory elements where differential DNA methylation accounted for inter-individual differences of lactase mRNA level in a Lithuanian cohort of individuals."

"Through regression modeling we show that DNA methylation in the enhancer and promoter site of the LCT gene, rather than differential regulation of intestinal transcription factors, e.g. CDX2, POU2F1, GATA4/6 or HNF1α, is predictive of lactase persistence/non-persistence."

"Most importantly, however, cross-validation analysis revealed that methylation at the LCT promoter and enhancer was highly predictive of lactase enzymatic activity, and the persistence/non-persistence phenotype. The predictive power outperformed the hitherto existing genotype at rs4988235, which fails prediction for the C/T genotype."

 

"In summary, we have investigated the contribution of epigenetics to the lactase persistence/non-persistence phenotypes, including lactase gene expression and enzymatic activity. We have identified putative lactase meQTLs, which are differentially methylated between lactase persistent and lactase non-persistent individuals."

My comment: C>T alteration is a common alteration in DNA and it typically occurs as a result from deamination of a methylated cytosine base. This study proves that methylation levels of MCM6 and LCT genes are more predictive for lactose tolerance phenotype than genetic mutations. That's why DNA mutations are often results from epigenetic modifications.

This study didn't take into account other regulatory mechanisms, such as miRNA upregulation, lncRNA regulation, histone epigenetic markers, gut bacteria, immune system etc. But this study shows that evolutionists' claims regarding random beneficial mutations are pseudoscientific claims. Random DNA mutations never result in any kind of evolution. Don't be deceived.