This Butterfly Is A Bilateral Gynandromorph: Literally Half Male, Half Female

May 26, 2016

A gynandromorph is an organism that contains both male and female characteristics. But this butterfly is a bilateral gynandromorph, which means one half is completely female and the other half is completely male.

butterfly half male half female

The cause of this phenomenon is typically an event in mitosis during early development.

While the organism is only a few cells large, one of the dividing cells does not split its sex chromosomes typically. This leads to one of the two cells having sex chromosomes that cause male development and the other cell having chromosomes that cause female development. For example, an XY cell undergoing mitosis duplicates its chromosomes, becoming XXYY. Usually this cell would divide into two XY cells, but in rare occasions the cell may divide into an X cell and an XYY cell. If this happens early in development, then a large portion of the cells are X and a large portion are XYY. Since X and XYY dictate different sexes, the organism has tissue that is female and tissue that is male.

Pretty cool, huh? But...which bathroom does it use?