Kangaroo genes could boost milk

By Becky McCall

Researchers want to find out why kangaroos are such hardy creatures

An Australian scientist says studying the kangaroo genome might help scientists modify genes in cows so that they produce highly nutritious milk.

Kangaroo milk production is of special interest to some scientists because the animals make three distinct types of milk depending on their embryo's age.

The research is part of the Kangaroo Genome Project, an Australian effort to sequence the marsupial's entire genome.

The research was discussed on Monday at the Human Genome Meeting in Berlin.

"In the future and after much debate, this gene could be implanted into a cow to make special types of milk," said Professor Jenny Graves, a scientist from the Australian National University.

The milk is packed full of growth factors. Such milk might be very useful for very young and premature infants Prof Jenny Graves, Australian National University

Milk production

By understanding the genes which switch milk production on and off in lactating kangaroos, the scientists could eventually incorporate such genes into the genomes of cows.

This might enable them to produce certain very specialized types of highly nutritious milk.

"I can see potential applications particularly suitable for very tiny embryos because a kangaroo embryo is about as big as a pea when born," said Prof Graves.

"It doesn't even have some of its organs yet so the milk is packed full of growth factors. Such milk might be very useful for very young and premature infants."

The Kangaroo Genome Project is a collaboration between Australia's lead geneticists to sequence the entire kangaroo genome in five years.

"By comparing the human genome with the kangaroo genome we can look back deep into the past because the two species last shared a common ancestor 180 million years ago," said Prof Graves.

Conserved genes

"So any conserved genes must have particular importance whilst any insignificant genes have changed. Mice only diverged 80 million years ago and are too closely related."

The kangaroo genome has also provided insight into the plight of the Y chromosome, which determines maleness.

The chromosome has been mysteriously shrinking over a long period of time. Current research predicts that there is unlikely to be a Y chromosome in nine million years.

The researchers believe that the kangaroo's Y chromosome is worth looking at because, as in humans, it is particularly short.

"We have looked at which genes on the Y chromosome of the kangaroo also feature on the Y chromosome of the human male," Prof Graves explained.

"This has led us to show that there is only a little teeny bit of the original Y chromosome left and this feeds into our vision of the Y chromosome as a very degenerate chromosome, losing genes all the time."

Research into the kangaroo embryo may also have implications for in vitro fertilization. Uniquely, the kangaroo embryo has the ability to stop and restart its development, almost entering a state of dormancy.

"We'd love to know what turns these signals in the embryo off and on from the point of view of manipulating embryos during in vitro fertilization and for contraception," said Prof Graves.