Un mundo sin hombres:Sera posible que la hembra "prefiera" tener cria sola antes que "usar" semen del macho.?

Un mundo sin hombres: "A pesar de tener machos alrededor esta "chica" tuvo hijos virgen" (por Partenogenesis)
Sera posible que la hembra "prefiera" tener cria sola antes que "usar" semen del macho..



First Virgin Birth in Boa Constrictors Discovered | Parthenogenesis & Asexual Reproduction | Snakes & Lizards | LiveScience: "'Is it possible that the female selectively chose not to utilize the male sperm if breeding occurred?' Booth said. 'Is it possible that the males were genetically incompatible with the female? We simply do not know enough about parthenogenesis in boas to speculate.'"

For the first time, scientists have discovered a boa constrictor that reproduces by virgin birth.

Intriguingly, these giant female serpents only gave birth in this fatherless manner in years when males were present, researchers added.

Asexual reproduction is common among invertebrates (animals without backbones), and is rare in vertebrates, but not unknown. For instance, the komodo dragon, the world's largest living lizard, has given birth via parthenogenesis, in which an unfertilized egg develops to maturity.

Scientists investigated a female boa constrictor at the Boa Store in Sneedville, Tenn., an online store that sells captive-bred boa constrictors. The female had given birth to litters of young this year and last. These offspring were all female and, unusually, were all caramel in color like their mother. This rare trait is recessive in nature, meaning it gets expressed only if offspring receive the DNA for it from both their parents, and none of the males that the female had been exposed to were known to carry the trait.

Genetic tests revealed that none of these litters carried any genes from any of the males their mother had known. The baby snakes must have been fatherless, the first time parthenogenesis has been seen in boas.

"It's perplexing that males were present with the female in years that she produced these parthenogenetic offspring, and in years when they were absent she did not," said researcher Warren Booth, a population and evolutionary geneticist at North Carolina State University at Raleigh. "Instances of parthenogenesis, or virgin birth, are often attributed to a lack of mates. Therefore, in cases where males are not present, the female would be better to produce parthenogenetic babies than none at all.

"Is it possible that the female selectively chose not to utilize the male sperm if breeding occurred?" Booth said. "Is it possible that the males were genetically incompatible with the female? We simply do not know enough about parthenogenesis in boas to speculate."