Known formally as parthenogenesis, virgin birth occurs when an embryo develops from an unfertilized egg cell. The development of an embryo usually requires genetic material from sperm and egg, as well as a series of chemical changes sparked by fertilization. In some parthenogenetic species, egg cells don’t undergo meiosis, the typical halving of the cell’s chromosomes, before dividing into new cells. These offspring are generally all female and clones of their mother. Other forms of parthenogenesis occur when two egg cells fuse after meiosis.
Biologists think that sexual reproduction evolved as a way to mix the gene pool and reduce the impact of harmful mutations. Still, parthenogenesis can be beneficial if the mother is particularly well adapted to her environment, since all of her offspring will be just as well adapted.
Here’s a glimpse at some of the world’s most recently discovered parthenogenetic species:
New Mexico whiptail (Aspidoscelis neomexicana)
Living in the deserts of the U.S. Southwest and parts of northern Mexico, the New Mexico whiptail is an all-female species of lizard. The creatures first arose as hybrids between two closely related species of sexually reproducing lizards: the little striped whiptail (A. inornata) and the tiger whiptail (A. tigris). Male hybrids aren’t viable, making this one of the few all-female species. Adult female New Mexico whiptails reproduce solely through parthenogenesis, laying unfertilized eggs that develop into other female whiptails.