Animal

‘Super Daddy’ pigs, goats and cattle could help combat global food shortages


Caption: Scientists genetically modify animals to create ’super daddy goats’

Scientists have created ‘super Daddy’ animals that can be ‘surrogate sires’ and potentially combat global food problems.

A US-UK team say they have ‘proof in principle’ that male pigs, goats and cattle can produce sperm carrying only the genetic traits of donor animals.

Scientists say the development could speed up the spread of desirable characteristics in livestock and improve food production.

Jon Oatley, a reproductive biologist with Washington State University’s College of Veterinary Medicine, explained: ‘With this technology, we can get better dissemination of desirable traits and improve the efficiency of food production. This can have a major impact on addressing food insecurity around the world.’

The genetically-modified animals could also give breeders in remote regions better access to the genes of ‘elite’ animals from other parts of the world.

It could also allow more precision breedings where artificial insemination is difficult, in animals like goats.

Mr Oatley continued: ‘If we can tackle this genetically, then that means less water, less feed and fewer antibiotics we have to put into the animals.’

In the more distant future, researchers hope the technology could also open help genetic conservation of endangered species, whose dwindling numbers limit their genetic diversity.

A gene-edited surrogate bull (Picture: PA)

Scientists used the editing tool CRISPR-Cas9, to knock out a gene linked to male fertility in the animal embryos that would be raised to become surrogate sires.

Although the male animals were born sterile, they began producing sperm after researchers transplanted stem cells from donor animals into their testes.

The sperm the surrogate sires produced only carried the genetic material of the selected donor animals, allowing specific characteristic to be reproduced.

The process outlined in the study — published in the Proceedings of the National Academy of Sciences journal — seeks to bring about changes within an animal species that could occur naturally, such as infertility.

It is the result of six years of collaborative work among researchers at WSU, Utah State University, University of Maryland and the Roslin Institute at the University of Edinburgh.

Washington State University reproductive biologist Jon Oatley feeding a goat ‘surrogate sire'(Picture: PA)

The researchers used CRISPR-Cas9 to produce mice, pigs, goats and cattle that lacked a gene called NANOS2, specific to male fertility.

The male animals grew up sterile but otherwise healthy.

After they received transplanted sperm-producing stem cells from other animals, they started producing sperm derived from the donor’s cells.

The surrogate sires were confirmed to have active donor sperm.

In the study, the surrogate mice fathered healthy offspring who carried the genes of the donor mice.

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However, the larger animals have not been bred yet, and Prof Oatley’s lab is refining the stem cell transplantation process before taking that next step.

The Roslin Institute’s Professor Bruce Whitelaw said the study provides a powerful proof of concept.

He added: ‘This shows the world that this technology is real. It can be used.

‘We now have to go in and work out how best to use it productively to help feed our growing population.’

Scientists have been searching for a way to overcome the limitations of selective breeding and artificial insemination, both of which require either animal proximity or strict control of their movement.

Researchers say the surrogate sire technology could solve the problem since the surrogates deliver the donor genetic material through normal reproduction.

That would allow ranchers and herders to let their animals interact normally.

The research also says donors and surrogates do not need to be near each other because either frozen donor sperm or the surrogate animal itself can be shipped to different places.

Meanwhile, females without NANOS2 remain fertile — since the gene only affects male fertility — and could be bred to efficiently generate sterile males to be used as surrogate sires

The technology has the potential to help food supply in the developing world, where herders still have to rely on selective breeding to improve their stock, Irina Polejaeva, a professor at Utah State University, said. 

She explained: ‘Goats are the number one source of protein in a lot of developing countries.

‘This technology could allow faster dissemination of specific traits in goats, whether it’s disease resistance, greater heat tolerance or better meat quality.’

But researchers admit that a lot of work needs to be done outside the lab before the modifications can be made to the animals.

Professor Oatley warned that it could take time for societies to accept the possible change and for governments to legislate to allow it.

Get in touch with our news team by emailing us at webnews@metro.co.uk.

For more stories like this, check our news page.

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