ALL IN THE GENES.

Shreyasee has a baby with thalaseemia major. Seeing her child having to undergo repeated transformations, she and her husband want to know if they can have an unaffected baby. They want to understand the risk of having another baby with thalaseemia major in the next pregnancy. Susheela had a baby with cystic fibrosis. The child died at the age of five. She and her husband are worried. Will they have another baby with cystic fibrosis?

Shreyasee and Susheela both have had babies with a genetic disorder. They need to be seen by a genetic counsellor. If there is a genetic disorder in the family, a genetic counsellor helps you understand your risk of having a baby with that disorder. If a couple  has already had a child with an inherited birth defect, genetic counsellors can help them understand what their chances are of having another baby with the same genetic disorder. They can also help them learn what testing, surveillance or prevention strategies are available.

The genetic counsellor draws up a family tree or pedigree chart which helps clarify the way the genetic disorder is being passed from generation to generation. Let us take the case of Shreyasee and her husband. Shreyasee came from a community where there was a lot of inter-marrying among close relations. This increased the chance of both being carriers of the disease. A carrier is a person who has both a normal and a defective gene. The genetic counsellor tested Shreyasee and her husband to find out if they were carriers of thalassemia. After DNA testing, both were found to be carriers. The counsellor told them that they had a 25% (1 in 4) chance of having  an unaffected (normal) baby, a 25% chance of having an affected baby and a 50% chance of a baby who will be a carrier. With their next pregnancy, Shreyasee underwent a chorionic villus sampling. This is a test where a small amount of tissue is aspirated from the forming placenta. The test showed that the baby was a carrier but did not suffer from the disease. The baby was born and has continued to stay healthy.

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ANCIENT AMPHIBIAN HAD WORLD'S ODDEST BITE. 

A peculiar amphibian that was clad in bony armour prowled warm lakes 210 million years ago, catching fish and other tasty snacks with one of the most unsual bites in the history of life on earth. The creature called Gerrothorax pulcherimus, which lived alongside some of the early dinosaurs, opened its mouth not by dropping its lower jaw, as other vertebrate animals do. Instead, it lifted back the top of its head in a way that looked a lot like lifting the lid of a toilet seat. 

"It's weird. It's the ugliest animal in the world", Harward University's Farish Jenkins, one of the scientists who describe the mechanics of its bite in the Journal of Vertebrate Palaeontology said. "You almost can't imagine holding your jaws still and lifting your head back to take a bite", Jenkins said. "There are some Vertebrates that will lift their heads slightly (when they bite). But no animal is known to have done it this extensively", Jenkins added.

The scientists think Gerrothorax lurked at the bottom of a lake, then with a sudden movement of the skull created a mouth gape that entrapped any fish unfortunate enough to swim by.

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C. S. Chakravarthy

H. No. 12-13-301, St. No. 9,
Lane. No. 1, Flat No. 203,
Satya Classic, Tarnaka, Secunderabad-500 017