How the embryo develops in the womb is a complicated process, that is still puzzling today. In particular, it is unresolved how the paternal genetic information that is also present in the embryo, and the emerging body cells based on their mixed "blueprint" are tolerated by the maternal immune system and not rejected upon recognition as foreign. While this process is now well understood in humans, pregnancies in the animal kingdom still provoke many unanswered questions. An international team under the leadership of the GEOMAR Helmholtz Centre for Ocean Research Kiel has intensively studied the unique male pregnancy in 12 species of pipefishes and seahorses. In some species, the males carry the eggs only on their trunk, in others they protect them by skin flaps or even placenta-like systems which supply the offspring with nutrients and oxygen.
“By comparing the genomes of pipefishes and seahorses, we discovered that in the evolution of male pregnancy, the immune system pathways responsible for self and non-self recognition have changed considerably”, explains Dr. Olivia Roth, from GEOMAR, first author of the paper which now appeared in the Proceedings of the National Academy of Sciences (PNAS). “Moreover, we detected that genes maintaining essential functions in female mammalian pregnancy, are also activated in male pregnancy. This suggests that pregnancy, whether male or female, relies on similar molecular mechanisms and that similar genes are altered in their function in the evolution of a pregnancy”, Dr. Roth continues.
Read more at Helmholtz Centre For Ocean Research Kiel (GEOMAR)
Photo: Sampling at the sea floor. CREDIT: P. Schubert.