Seahorses are the only animal with stay-at-home dads

DNA analysis showed gene expression in pregnant male seahorses is very similar to gene expression in expecting human moms.
By Brooks Hays  |  Sept. 3, 2015 at 9:49 AM
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SYDNEY, Sept. 3 (UPI) -- Researchers knew male seahorses were more involved in parenting than their animal peers -- they carry the pregnancy, after all. But until now, scientists didn't have the full picture.

It turns out, most of the rearing responsibilities are shouldered by dad.

A new study shows male seahorses, in addition to nurturing their growing embryos, continue to feed and protect their offspring post-pregnancy.

"Surprisingly, seahorse dads do a lot of the same things human mums do," researcher Camilla Whittington, with School of Biological Sciences at the University of Sydney in Australia, said in a press release. "Seahorse babies get a lot of nutrients via the egg yolk provided by their mothers but the pouch of the fathers has also evolved to meet the complex challenges of providing additional nutrients and immunological protection, and ensuring gas exchange and waste removal."

Whittington is the lead author of a new paper on pregnancy and rearing among Australian pot-bellied seahorses, published Wednesday in the journal Molecular Biology and Evolution.

To better understand seahorse pregnancy, researchers took small tissue samples from males' brooding pouches during gestation. DNA analysis showed gene expression in pregnant male seahorses is very similar to gene expression in expecting human mothers.

Though a mom's egg yolk provides the embryo essential nutrients, a father's brood pouch is also vital to the embryo's maturation. A father's lipids give the growing seahorses energy, and his calcium helps the miniature seahorses' tiny bones to strengthen.

"Regardless of your species," said Whittington, "pregnancy presents a number of complex challenges, like ensuring you can provide oxygen and nutrients to your embryos. We have evolved independently to meet these challenges, but our research suggests that even distantly related animals use similar genes to manage pregnancy and produce healthy offspring."

Whittington and her colleagues say they're already planning further research. The evolution of animal pregnancy may be more consistent across species than previously thought.

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