Gender Benders

Sex is a strangely shifting phenomenon in the oceans, and this gender bending is more common than you might ever have realised!.

- Chetana Purushotham

IN 2003, a surprise event transformed our perception of life in the ocean. This transformation came rather unexpectedly from a heart-warming animated children’s movie, called Finding Nemo. The story of a widowed clownfish’s search for his abducted son, Nemo, changed the general understanding of the ocean as a vast monotonous blue, to a colourful world where Nature’s imagination seems to have run wild. The surprising level of scientific detail in the film taught a generation a lesson in marine biology and conservation, with every laugh and tear.

However, the makers of the film could only go so far in accurately depicting the life-history of its protagonists (the clownfish family) without severely convoluting the plot. Clownfish, like several other fish families, are “hermaphrodites”, which means that they can and will manipulate their sexuality at least once in their lifetime. How would the audience have responded if they knew that in reality Nemo would have been born, not as a male, but in fact, genderless? “He” would eventually have transformed into a male, once his father had turned female following Nemo’s mother’s death.

SHIFTING SEXUALITY

Can we imagine a world where our gender and sexuality is almost guaranteed to change during the course of our lives? Where sexuality is determined, less by our genes at the time of conception, and more by the number of men and women living in our peer group? To think that an individual could change from one sex to another after attaining maturity or to take the place of a lost member of its society, seems absolutely bizarre. Yet this is the norm in the world of fish (and some other marine invertebrates). An adaptation that has evolved independently at different points in fish ancestry, sex change offers its adopters a strong reproductive advantage.