Sequential hermaphroditism (or why to be wary of frog DNA)

The sixth in a series from the blog Gender and Sexuality in Nature, a 2016 UC Davis course organized by UM EEB alumnus Ash Zemenick (UM EEB B.S. 2011, Ph.D. UC Davis 2017) and Jacob Moore (B.S. University of Washington 2009, Ph.D. UC Davis 2017).

Last week, we discussed one type of hermaphroditism: simultaneous (also known as synchronous) hermaphroditism, in which an individual produces both eggs and sperm at the same time.

This week, we moved on to the other type of hermaphroditism: sequential hermaphroditism. A sequential hermaphrodite is an individual that changes (or has the capability to change) sex at some point in its life, meaning it can produce both eggs and sperm over the course of its lifetime (but not at the same time). A sequential hermaphrodite can start as female and change to male (called protogyny, meaning “female first”) or start as male and change to female (called protandry, meaning “male first”).

Sequential hermaphroditism is widespread among plants, invertebrates (including some snails, sea stars, etc.), and fish. I didn’t know it at the time, but I was first introduced to the idea of sequential hermaphrodites in one of my favorite movies: Jurassic Park. In case you have never watched Jurassic Park (blasphemy!) or have forgotten the details, the lead scientist is sure that the dinosaurs they have created are unable to reproduce because they were designed to all be female. However, as Jeff Goldblum’s character famously points out.

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For materials and information on teaching sex- and gender-related topics in biology see  Reposted with permission with the caveat that these posts are several years old and Project Biodiversify and other efforts like Gender Inclusive Biology and other LBGTQIA2+ people are always working to improve and update.