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Y chromosome man finds nature's failsafe
Papri Sri Raman, IANS
Chennai, September 15, 2007
First Published: 23:29 IST(15/9/2007)
Last Updated: 23:58 IST(15/9/2007)

Sher Ali hopes that there will never be a nuclear holocaust. But even if there were one, humankind would still survive on earth, says India's Y chromosome man.

One of the fallouts of a nuclear holocaust, Ali said, is that the reproductive cells in men are destroyed or genetically so modified that either there are no offspring or they are malformed.

Ali's study of natural radiation victims on Kerala's coast has revealed nature's unique way of protecting the species. The findings have been significant enough for the Bhabha Atomic Research Centre take notice of them.

Sher Ali, a professor at the molecular genetics division of the New Delhi-based National Institute of Immunology (NII), is an archetypical government scientist. The seemingly frail Ali has spent years for project grants to arrive and works without even the assurance of a pension to look forward to.

This unknown scientist is content with the applause he receives from the small community of cell biology students in India.

A product of the Aligarh Muslim University, Ali was Alexander Von Humboldt Fellow at the Max Planck Institute for Immunology in Germany and a researcher at the City of Hope National Medical Centre in the US in the early 1980s before returning to India to join the NII in 1989.

Invited by the British Council and the Centre for Biotechnology at Anna University in Chennai to talk about the Y chromosome at a seminar on "Biotechnology: India-UK Perspective", the diminutive Ali was self-effacing about his work.

For the past four years, Ali and his team of researchers have studied the effect of "natural background radiation (NBR)" that occurs from sunlight and thorium deposits on the beaches of Kottayam in Kerala.

The study was done on 600 men in Chowara village in Kottayam, 300 of them exposed to NBR. He also studied naturally aborted foetuses from the area, which the mother's body had rejected because of some deficiency.

Two sets of comparative studies were done on blood (the body cell) and semen (the reproductive cell) to study their Y chromosomes.

In humans, the X and Y chromosomes are known as sex-determining chromosomes. Women have cells containing two X chromosomes and men have one X and Y chromosome each.

The Y chromosome is supposed to have been present in the species for 300 million years and is much studied. The Y chromosome is about one fourth the size of the X chromosome. It is a ragged and tattered mess, with many missing patches.

Scientists like Jennifer A Marshall Graves from the Australian National University and Alan Trounson, professor of early human development from the Monash Institute of Reproduction and Development in Australia have been for a decade talking of it vanishing altogether from the species.

What will happen then? Well, the way people have sex will certainly change.

The world will be filled with two kinds of women, those with two X chromosomes and those with just one X chromosome.

"It isn't all that bad yet", Ali told IANS. "It will take a million years to happen and may not happen this way at all," he adds, based on the findings of his Kerala study.

In four published papers, Ali has elaborated on how the Y chromosome is affected by natural radiation.

The genes of the Y chromosome hold a secret. Although they may be ramshackle, they have hidden duplicates, some genes duplicating more than 100 times.

Y chromosome in the study sample's blood cells were hurt due to the natural background radiation but the Y chromosomes in their reproductive cells (germ line) were found to remain intact. These men had normal children.

Ali and his team zeroed in on the gene called the DAZ gene in the Y chromosome and tracked it. They found there were four copies of this gene in normal males and as many as 16 copies of it in those exposed to NBR.

"Startlingly, all the germ line (semen) samples studied were found to be free from micro-deletions and C-type peptides of the DAZ genes (protein degeneration)," Ali said.

This means nature has a way of duplicating and hiding the precious part of the male gene in the reproductive cells, even when exposed to radiation of any kind.

In other words, if one could ensure that the DAZ gene existed and worked in the human body, the male of the species would survive.

This natural protection of the germ line is what has interested nuclear scientists most. The findings could have stellar applications in understanding how genes work and how radiation could split genes.

The Department of Atomic Energy has now invited Ali to talk to India's nuclear establishment about his findings.


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