Human Origins: A Genomic Approach
“And then God created man in his own image…”
A hundred thousand years ago, Darwinian evolution conceived a remarkable species-one that was destined to change the landscape of this planet- Homo sapiens. This species had emerged out of a complex and intricate framework of natural selection working over ages that radiated from primitive apes. The story of becoming human is more fascinating than any work of fantasy or fiction ever written. How did we come here? What made us what we are? These questions have always appealed to human imagination. We have had our set of answers throughout history and Science has offered us the courage to ask these fundamental questions again with a new perspective – one which is not based on dogma or belief, but which is backed by evidence and scepticism. A new wave of science is reckoning now which promises insights into the human story like never before. It is the science of the genome.
The human genome is a complicated maze of nucleotide sequences that has evolved along with our species to deliver changes in our design. These changes accumulated over generations and made us the way we are today as contemporary humans. Tracing back the history of our genome can help us peep into our remote past. There are two major approaches to this hypothesis- the mtDNA study and the Y chromosome study. Human mitochondrial DNA is a sequence of 16,569 bp and is maternally inherited. It is estimated to adopt one mutation every 25000 years which makes it reasonably suited for evolution studies. (The nuclear DNA is much more stable and therefore difficult for such analysis.) Now, different mtDNA sequences correspond to different populations and hence can be used to map migration patterns. Moreover, ancient DNA extracted from fossils make the phylogenetic study of hominin populations feasible. Comparing the DNA markers across modern human populations as well as ancient hominid populations can help us build a genetic tree of human evolution. Moreover, Y chromosome studies, although more scarce, corroborate with implications of mitochondrial DNA data and provide deeper insights into our species’ development.
Human evolution is marked by milestones in the social and cultural aspects of our existence. These great events too had lasting impacts on our genome. The growth of agriculture made our diet more varied with obvious impact on our metabolic biochemistry reflected back in our DNA. Language too played a crucial role in the diversification of human genome across populations. The Out of Africa (OAA) migration of modern humans has received some great scientific consensus based on mtDNA studies. The major haplogroups of human mtDNA have been successfully traced back to the migration pattern of our ancestors.
These remarkable achievements in our scientific quest for understanding our own origins have no doubt elevated the human spirit. The exposure of human intellect to its own history is something that is unparalleled. In those ancient records of our infancy and growth as a species lies the promise of our future as a civilization. And somewhere from those landmarks of man’s journey echoes what Jacob Bronowski reminded us of-
“This is my mark. This is man.”http://www.geneticengg.com/2017/06/01/human-origins-a-genomic-approach/http://www.geneticengg.com/wp-content/uploads/2017/06/nrg3966-f5.jpghttp://www.geneticengg.com/wp-content/uploads/2017/06/nrg3966-f5-150x150.jpgGeneticsevolution,genome,human genome,mtdna,phylogeny,Y chromosome“And then God created man in his own image...” A hundred thousand years ago, Darwinian evolution conceived a remarkable species-one that was destined to change the landscape of this planet- Homo sapiens. This species had emerged out of a complex and intricate framework of natural selection working over ages that...Rajit RoyRajit Royrajit.email@example.comEditorGeneticEngg.com