Short Science, April 21, 2013

PUBLISHED : Sunday, 21 April, 2013, 12:00am
UPDATED : Sunday, 21 April, 2013, 4:39am

Zebrafish helping fight disease in the lab

One of the world's most popular aquarium fishes has joined the rat, the mouse, fruit fly and nematode worm in the roll call of creatures whose DNA has been sequenced to help fight disease among humans. A consortium of researchers unveiled the genome of the zebrafish in the British journal Nature, declaring it made a vital model for pinpointing faulty genes. The tiny striped fish - with the scientific name Danio rerio - has 26,000 genes, 70 per cent of which are shared with humans. Eighty-four per cent of genes known to be associated with human disease have a zebrafish counterpart. The fish has a brief life cycle and in the embryonic stage is transparent, which makes it highly useful in the lab. The zebrafish has already unlocked insights into cancer and heart disease, and advanced knowledge of muscle and organ development, including genes implicated in muscular dystrophy. "We can readily create variations in their genome that are relevant to human health and disease. This has allowed a greater understanding of gene function and the finding of new targets for drug treatments," said Leonard Zon of the Children's Hospital of Boston, Massachusetts. AFP


Does mum have better baby sense? Not really

French researchers have dealt a blow to folklore that says mothers are better than fathers in recognising their baby's cry. The "maternal instinct" notion gained scientific backing more than three decades ago through two experiments, one of which found that women were nearly twice as accurate as men in identifying the cry of their offspring. But the new study says men and women are equally skilled at this - and accuracy depends simply on the amount of time that a parent spends with the child. Scientists led by Nicolas Mathevon at the University of Saint-Etienne recorded the cries of 29 babies aged between 58 and 153 days as the infants were being bathed. Fifteen of the babies were in France and 14 in the Democratic Republic of Congo. The idea of sampling cries in Africa and Europe was to test whether local culture and family habits affected outcomes. All the mothers, and half of the fathers, spent more than four hours a day with their baby. The other fathers spent less than four hours daily with the child. The parents were asked to listen to a recording of three different cries from five babies of a similar age, one of which was their own. There were two sessions of experiments. On average, the parents were 90 per cent accurate in identifying the cry of their own baby. AFP


Genes of 'living fossil' fish are mapped

Biologists said they had unravelled the DNA of the coelacanth, a "living fossil" fish whose ancient lineage can shed light on how life in the sea crept onto land hundreds of millions of years ago. Analysis of the coelacanth genome showed three billion "letters" of DNA code, making it roughly the same size as a human's, they said. The genetic blueprint appears to have changed astonishingly little over the aeons, pointing to one of the most successful species investigated. "We found that the genes overall are evolving significantly slower than in every other fish and land vertebrate that we looked at," said Jessica Alfoeldi, of the Broad Institute of the Massachusetts Institute of Technology and Harvard. Found in deep waters off South Africa, with cousins off the coast of Indonesia, coelacanths are one of the oldest species that exist today. The grey-brown fish can grow up to two metres in length and weigh as much as 91kg. AFP