Human traits. Are they arriving on time?

By Marta Koblańska, January 29, 16:55, Photo: public domain Pixabay

Is it possible to catch differences in human genome visible and invisible expression? Modern technologies enable so. And what’s more they can trace our past to millions of years back.

Natural selection which is an ongoing process of passing traits from one generation to the next and next, parks, lets say, prints in our genome.
Of course, we are all humans and we gained complex human traits which made us creatures we are with strong differences from our ancestors. But, as Australian-based scientists state in newly published article in ,,Cell Genomics” during millions of years of evolution, we may have collected many variants but sometimes with small effects. One or another, discoveries of strong selective sweeps remain rare. Moreover, due to reproducing our genes we may adapt, as a population to an environmental change by subtly altering allele frequencies across many variants – Jian Zeng writes in the article ,,Tracing human trait evolution through integrative genomics and temporal annotations”. Alleles are these versions of our genes whose expression may differ as they are built by slightly different nucleotides (the base of our genetic code which replicates, sometimes makes mistakes and a substantial portion of which we share with other mammals).

Footprint for future

This is why it is difficult to trace the genetic evolution in complex traits.
But it does not mean it is impossible. Nowadays technologies, genome advanced sequencing in particular, which maps genetic variants associated with phenotypic variation of traits, and genomic annotations (expression) may deliver us information on functional roles of genetic sequences/regions as well as on differences between them. Currently both wide lengths and the small ones could be read. Moreover the technology enables to track a sense of enrichment in our genome what may be a footprint of our past and, in some sense – future.

Scientists from Brisbane, Australia (The University of Queensland), focused on 70 complex human traits and diseases over past 25 million years since divergence from rhesus macaques, chimpanzees, and Neanderthals and Denisovans. Meanwhile, the analysis investigated the timing of accelerated genomic changes. The obtained data indicated 11 genomic annotations linked to studied across species as well as developmental stages. What’s more the authors of the study could mark regions that evolved during different periods of human evolutionary history back to 25 millions years. That was the time when our human traits became somehow enhanced in the genome.

Significant heritability and gene enrichments were observed for skeletal traits, consistent with fossil evidence, highlighting adaptations related to bipedal locomotion and body structure.

says Jian Zeng of University of Brisbane

The scientist adds, signals were also found for respiratory traits linked to lung function as well as white matter measurements in the brain’s left part, which is associated with language processing. Further divergences strenghten specified traits such as body mass index, smoking status or visual cortex along with psychiatric traits which could have been linked, according to previous studies to paths of lung and brain development. What’s interesting currently very common dysfunction – autism may come from Neanderthals whose went extinct due to many reasons and dates back 5 million years. As scientists state in their article, applied techniques revealed heritability enrichment for autism in ancient selective sweeps. This could suggest incomplete selection on autism-associated variants due to pleiotropic effects on neural development and cognition. Pleiotropic effect, a popular solution in a lot of modern medicines, help to alleviate pain we feel because our brain work in a way we do not really want, what does not always imply improperly.

Scientists conclude their study for the first time reveal phenotypic evolution with distinct genomic changes over millions of years. – These efforts lay a foundation for future research to uncover the evolutionary dynamics underlying human health and disease – state scientists. However, the question could be whether we prefer to know everything on our past and so-called future?