From Patricia Edmonds at National Geographic:
The lizards are all female and parthenogenetic, meaning their eggs develop into embryos without fertilization. But before the eggs form, Baumann’s team discovered, the females’ cells gain twice the usual number of chromosomes—so the eggs get a full chromosome count and genetic variety and breadth (known as heterozygosity) rivaling that of a sexually reproducing lizard.
Why does this occur? Because long ago, Baumann says, lizards of the genus Aspidoscelis had “a hybridization event”—that is, females of one species broke form and mated with males of another species. More.
It’s still not clear how this closed system would not lead to genetic degradation over time. But we shall see.
See also: Red wolf not endangered, a hybrid?
Grizzly-polar bear hybrids in the Arctic
Life continues to ignore what evolution experts say
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