Gene causing arthritis may have helped humans survive Ice Age: Study

New York: A new study has showed that a gene linked to increased risk of osteoarthritis and reduced height might have helped our ancestors survive the Ice Age.

According to the study, mutations in the gene called GDF5 resulted in shorter bones that led to a compact body structure while reducing the risk of bone fracture from falling.

The finding also favoured early humans to better withstand frostbite as well as helped them migrate from Africa to colder northern climates between 50,000 and 100,000 years ago.

Researchers said, these advantages in dealing with chilly temperatures and icy surfaces may have outweighed the threat of osteoarthritis, which usually occurs after a prime reproductive age.

Terence Capellini, Associate Professor at the Harvard University said,"The variant that decreases height is lowering the activity of GDF5 in the growth plates of the bone. Interestingly, the region that harbours this variant is closely linked to other mutations that affect GDF5 activity in the joints, increasing the risk of osteoarthritis in the knee and hip."

For the study, tshe team examined gene GDF5, the first linked to skeletal growth in the early 1990s, to learn more about how the DNA sequences surrounding GDF5 might affect the gene's expression.

They identified a single nucleotide change that is highly prevalent in Europeans and Asians but rarely occurs in Africans.

Introducing this nucleotide change into laboratory mice revealed that it decreased the activity of GDF5 in the growth plates of the long bones of foetal mice.

David Kingsley, Professor at the Stanford University said,"The potential medical impact of the finding is very interesting because so many people are affected."

Kingsley said,"This is an incredibly prevalent, and ancient, variant. Many people think of osteoarthritis as a kind of wear-and-tear disease, but there's clearly a genetic component at work here as well. Now we've shown that positive evolutionary selection has given rise to one of the most common height variants and arthritis risk factors known in human populations."

The study was published in the journal Nature.

(With IANS inputs)