Researchers at Bath University in the U.K. generated thousands of breathless headlines earlier this month, when they announced that they had created baby mice from sperm alone -- no egg required.
In today's DNews report, the first of a special two-part series, Jules Suzdaltsev sorts through the science to reveal that many of those headlines -- if not most, if not all -- were fundamentally misleading. No blame. Headlines are tricky.
First, a quick historical primer. Up until the 1820s, most scientists actually believed that humans came pretty much exclusively from sperm. The general idea was that each sperm contained a teeny-tiny baby that more-or-less grew into a bigger baby in the womb. In 1827, Estonian scientist Karl Ernst Ritter von Baer, Edler von Huthorn -- that's his full name -- figured out embryology, and the mammalian egg finally got its due.
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In 2004, another significant development took place when scientists figured out a way to essentially trick egg cells into thinking they were fertilized. The eggs began growing and dividing, but lacking paternal chromosomes, eventually petered out after a few days of development.
That brings us to the Bath University study, wherein researchers were able to fertilize a type of embryo called a haploid parthenogenote, which is not an egg cell, technically speaking. The scientists were indeed able to create healthy baby mice this way, but there's a catch: The haploid parthenogenote which the scientists managed to fertilize is derived directly from... a female unfertilized egg.
In fact, it's an egg in the exact same stage of development previously mentioned, where scientists tricked it into dividing. The study is still groundbreaking for many, many reasons, and represents a major step forward in embryology. But it's not like we can make a baby out of sperm and whatever is handy. We still need those eggs.
-- Glenn McDonald
Nature: Mice produced by mitotic reprogramming of sperm injected into haploid parthenogenotes
NewScientist: Zapped human eggs divide without sperm
CNN: Baby mice created from sperm, without an egg