Animals who are both male and female offer insight into evolutionary development

A very odd creature flitted past friends James Adams and Irving Finkelsteinโ€”a swallowtail unlike any they had ever seen. Its left half was yellow; its right, black. It was as though someone had sliced up two different insects and seamlessly sewn them back together. He could see immediately that he had caught a gynandromorphโ€”an animal that was half-male and half-female.

For hundreds of years, naturalists have been documenting gynandromorphs among insects, spiders, lobsters, and birds. More recently, researchersโ€”aided by increasingly sophisticated laboratory toolsโ€”have overturned reigning theories of sexual development by studying such hybrids. As has proven true time and again throughout the history of science, the creatures that seem strangestโ€”those that are too odd, too asymmetrical to fit neatly into our presupposed categoriesโ€”teach us the most about how all living things work. It turns out, for example, that the standard explanation of how a bird becomes male or female is wrong. Scientists came to this realization not by investigating scores of typical birds, but rather by examining a few gynandromorphs. It all started with an odd zebra finch.

Read the full, original story: Half Male, Half Female, Total Animal

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