The ethics of genetic combinations

SINCE ancient times, we have been aware of several basic ideas of heredity. Plants and animals with superior characteristics were isolated and multiplied. Human mating practices were restricted to exclude incest, as well as matings outside specific defined groups.

It's mama's fault

PEOPLE who suffer wild swings of moods -- from ecstatic highs to melancholic lows -- have their mother to blame. At least this is what researchers at Johns Hopkins Hospital, USA, suggest: Every woman on a sprawling family tree they have drawn up passes this disorder, called the manic-depressive psychosis, to her children, but no man suffering from it does.

Is violent behaviour hereditary?

VIOLENT aggression in humans may be because of a genetic defect, a recent Dutch study suggests. Han G Brunner and his colleagues at the University Hospital in Nijmegen report that a change in the gene coding for an enzyme called monoamine oxidase A (MAOA) may be responsible for unprovoked, aggressive outbursts displayed by certain males in a Dutch family that the researchers have been studying for the past ten years (Science, Vol 260, No 5115).

Is it a gene defect?

PEOPLE with strong body odour may probably be carrying a faulty gene, according to researchers from London's St Mary's Hospital Medical School. The researchers say they are close to nailing the gene defect because of which the carriers cannot process a chemical called trimethylamine, a product of digestion that smells of rotting fish. As a result, the chemical shows up in sweat, urine and the breath of such people.

Older than age

SCIENTISTS have discovered a gene that could make a person more prone to developing Alzheimer's disease -- a brain disorder that induces premature senility -- after the age of 65. The suspected gene codes for a protein that transports cholesterol through the bloodstream and researchers have found abnormally high levels of the protein in the brains of Alzheimer's patients (New Scientist, Vol 139, No 1887).

Paralysing gene

Paralysing geneUS SCIENTISTS have homed in on a gene defect linked to a debilitating nerve disorder known as Lou Gehrig's disease (Cambridge University Alumni Magazine). The disease, a celebrated victim of which is physicist Stephen Hawking, the author of A Brief History of Time, gradually paralyses its victims by killing off the nerve cells that control muscles. While the researchers found only a fraction of Lou Gehrig victims had this genetic mutation, they believe insights obtained from this discovery could shed some light on other cases.

Are your organs in the right place?

IF YOUR heart is in the wrong place, perhaps a gene is responsible for it. Researchers have recently identified a gene that plays a major role in deciding whether the internal organs in mice should be assigned to the right or left of the body and this has initiated the search for similar genes in human beings (Science, Vol 260, No 5108).

Culprit gene found

AFTER ten years of frustrating toil, a band of gene-hunters from USA and the UK have at last nabbed the gene that causes Huntington's disease, a debilitating disorder of the nerves. The researchers are hopeful the discovery will provide a better understanding of what causes the nerves to degenerate, and therefore, possibly a cure (Science, Vol 260, No 5104). Huntington's disease is hereditary and typically strikes people in middle age, debilitating them both me physically and mentally. HIV-1 wt Death usually occurs 10 transmitted

Bubble baby

FIVE-DAY-OLD Andrew Gobea became the first newborn to undergo gene therapy when surgeons at a Los Angeles hospital injected him recently with gene-altered cells obtained from his mother's placental blood to cure a usually fatal defect in his immune system. Andrew suffers from bubbly bay disease and lacks an enzyme that's essential to fight infection.

Protein provides clue to Alzheimer's disease

WHEN HARVARD researchers Bruce Yankner and Neil Kowall discovered in 1991 that amyloids -- small proteins -- injected into the brain of rats could destroy nerve cells in the same manner as observed in Alzheimer's patients, there was much excitement. Alzheimer's disease is the fourth largest killer in the developed world -- while USA spends $80 million every year to care for an estimated 4 million victims, UK has some 500,000 people afflicted by the disease, and the numbers are increasing steadily.