Homologous structures in fractally uncompressing terraforming machines
Science | Live birth has evolved repeatedly across the major taxonomic groups, but in the vast majority it is the female that does the brooding. The most developed case of gender reversal in brooding occurs among seahorses. In some seahorse species, males not only incubate the eggs internally but develop a pouch structure that is strikingly similar to a uterus in terms of form and function. Whittington et al. produced a detailed transcriptome of the genes up-regulated during pregnancy in male Hippocampus abdominalis and found that those involved in embryo growth and support functions, such as nutrient transport and waste removal, were generally homologous to those seen in pregnant female mammals and reptiles. Thus, it seems that the pregnancy pathway is much the same whether fish or mammal, female or male .