Plant breeders hunting for genes to combat new diseases or adapt to changes in climate can plumb the vast diversity of crops and their wild relatives using envelopes of seed banked in cold storage, but cattle breeders are limited to herds here and now, according to an announcement from Cornell University.
A new $500,000 U.S. Department of Agriculture grant, however, is funding research on a new, stem cell-based system that could capture global herd diversity in a subzero vault.
“Right now the repositories for breeding and research only store sperm, but sperm is not an inexhaustible resource — you can't make more once it runs out — and it only contains half the genome; the other half would be provided by eggs,” said principal investigator Vimal Selvaraj, assistant professor of animal science at Cornell. “So although cows are technically abundant around the world, artificial insemination using relatively few bulls of a few breeds is making cows 'genetically endangered.'”
Problems related to low diversity are already appearing, said Selvaraj, including infertility, reduced conception rates and fewer cycles of lactation, which results in lowered milk production. In addition, herds of the future may need genes that are in danger of being bred out.
“Many interesting indigenous breeds of cattle in Asia and Africa are disappearing as they are bred with Holstein or Jersey sperm to boost milk production,” he said. “Ankole cattle from West Africa are hardy animals that are able to withstand harsh climate with limited water resources, a drought tolerance that could be very important in the future. This technology would allow us to put the brakes on the loss of genetic diversity.”
The grant will enable Selvaraj to pursue a method to preserve cow diversity using induced pluripotent stem cells. Unlike stem cells that are made from embryos, these are coaxed from mature cells. With the right exogenous factors and chemicals, they can be reprogrammed to be induced into primordial cells capable of becoming many cell types.