Original title: Pregnancy establishment in cattle without embryonic interferon tau
Asghar Ali, Valeri Zakhartchenko, Tuna Güngör, Stefan Nüske +15 · October 2026
In cows, a growing embryo was believed to need a specific chemical signal called IFNT. Without this signal, the mother's body was thought to restart its cycle and end the pregnancy. Scientists used gene editing to remove every copy of this signal from cattle embryos. Surprisingly, the embryos grew normally, the mothers stayed pregnant, and healthy calves were born. This proves the long-studied signal is not actually needed.
A fire station has an alarm that blares whenever there is a genuine emergency. If the power cuts out and the alarm never sounds, firefighters expect to miss the call completely. In this paper, scientists cut out the signal that everyone thought was the only alarm telling the mother's body that an embryo was growing. Yet the mother's body responded as if the alarm had sounded anyway, proving another silent signal must be doing the job.
For decades, textbook biology claimed a specific embryonic signal was strictly required for cows to recognize a pregnancy and stay pregnant. Knowing that calves can be carried to term without it means other unknown biological signals are keeping the pregnancy alive, changing how scientists view cattle reproduction.
The abstract does not identify what alternative signaling mechanisms are keeping the pregnancy alive, nor does it test whether this finding applies to other ruminant species.
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Pregnancy establishment in cattle without embryonic interferon tau — Asghar Ali, Valeri Zakhartchenko, Tuna Güngör et al. — Nature Communications — doi:10.1038/s41467-026-78446-4
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.