A juvenile smalltooth sawfish in the Charlotte Harbor estuarine system in Florida. (Florida Fish and Wildlife Conservation Commission (FWC))
by Deborah Netburn
Desperate times call for desperate measures, which may explain why some critically endangered smalltooth sawfish are reproducing asexually in the wild.
The smalltooth sawfish is a member of the ray family, and under normal circumstances it reproduces sexually like most other vertebrates. However, in a study published in Current Biology, scientists report seven instances of juvenile sawfish that appear to be the product of a virgin birth — no dad involved.
The researchers were able to tell that these fish were produced asexually because routine DNA tests showed there was little to no variability in the genetic material of the seven specimens.
Asexual reproduction in a sexually reproducing species is called facultatitve parthenogenesis. Scientists think it occurs when an unfertilized egg absorbs a genetically identical sister cell called a polar body.
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