The latest research conducted by evolutionary biologists from various countries has brought forward intriguing insights into our genetic heritage and its impacts on our health. The study reveals that certain regions of the human genome, both those that make us susceptible to severe illness and those that protect us against the SARS-CoV-2 virus, have been inherited from Neanderthals. Once believed to be our closest extinct relatives, Neanderthals evolved alongside and later interbred with our own species, Homo sapiens, sharing their distinct genetic patterns.
Key Findings Inherited From Neanderthals
The research showed that a region on the host chromosome 3 acts as a significant genetic risk factor towards falling seriously ill. On the flip side, several groups of genes located on chromosomes 6,12,19, and 21 were found to protect us from the virus. The stretch of 50,000 nucleotides (basic building blocks of DNA) shared between modern humans and Neanderthals on chromosome 3 is part of this genetic mosaic.
Around 50% of South Asians were found to carry this region in chromosome 3 from Neanderthal genomes. This same region confers an increased risk of severe illness resulting from the virus. Moreover, the protective segment of chromosome 12 also originated in our Neanderthal ancestors. Interestingly, nearly 30% of South Asians bear this part of chromosome 12.
Implications of The Genetic Heritage
Since viruses can only survive and multiply in host cells, understanding the host genome is critical for studying both susceptibility and protection against viruses in a given population. Some genes inherited from Neanderthals act as protective shields against the virus, preventing severe disease. However, others predispose carriers to a higher risk of serious illness.
Understanding Human Evolution
Human evolution refers to the evolutionary process that resulted in the emergence of anatomically modern humans. This process started with the evolutionary history of primates, particularly genus Homo, and led to the emergence of Homo sapiens as a distinct species of the hominid family, the great apes.
Stages of Human Evolution
The path of human evolution was marked by various stages, beginning with Dryopithecus followed by Ramapithecus, Australopithecus, Homo habilis, Homo erectus, Homo sapiens, Homo sapiens neanderthalensis and finally Homo sapiens sapiens.
Neanderthals: Our Closest Extinct Relatives
Neanderthals (Homo neanderthalensis, Homo sapiens neanderthalensis) are members of a group of archaic humans. Neanderthals emerged at least 200,000 years ago and existed until they were replaced or assimilated by early modern human populations (Homo sapiens) between 35,000 and 24,000 years ago.
Genome: The Blueprint of Life
A genome comprises all the genetic material within an organism. It is defined as an organism’s complete set of Deoxyribose Nucleic Acid (DNA), including all its genes. In humans, a copy of the entire genome contains more than 3 billion DNA base pairs.
Chromosomes: Packaging for DNA
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome consists of DNA tightly coiled around proteins termed histones that support its structure. In humans, each cell normally contains 23 pairs of chromosomes, totaling 46. Twenty-two of these pairs, called autosomes, look identical in both males and females. The 23rd pair, the sex chromosomes, differs between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.
