An Important Development

The journey towards making the next generation starts at the very earliest stages of life. Certain special cells, known as germ cells, that will go on to form eggs or sperm in the adult are marked out in every embryo within the first few days of development. Researchers have discovered that zebrafish embryos with a faulty version of a gene called Igf2bp3, like the one shown here, usually develop as males. If any do become females, then they tend to have defective eggs. Looking more closely, they noticed that a region called the yolk syncytial layer, sandwiched in between the green and blue parts in this image, is larger than normal in these defective embryos, which could explain why they don’t develop properly. The Igf2bp3 gene has counterparts in other species, including our own, so this research could shed light on problems with sex development and infertility in humans too.

Written by Kat Arney

Kat Arney

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Dr Kat Arney is an award-winning science writer, broadcaster and public speaker, and is the founder and Creative Director of First Create The Media.

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• Image from work by Yin Ho Vong and colleagues, on the cover of PLOS Genetics, August 2021
• Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in PLOS Genetics, July 2021