All articles tagged with #asexual reproduction
Scientists thawed a 24,000-year-old rotifer preserved in Siberian permafrost, revived it under strict lab conditions, and observed renewed metabolism and asexual reproduction, showing that multicellular life can endure cryptobiosis for millennia. The finding has implications for biotechnology and astrobiology, though researchers caution that revival of larger animals is unlikely.
Researchers show that the clonal Amazon molly uses gene conversion to sustain natural selection: it creates new clonal lineages by reverting or fixing mutations and resolves incompatibilities between parental haplotypes, slowing degenerative mutation accumulation (Muller’s ratchet) while preserving parental divergence and altering chromatin organization in the transition to clonality.
A rare asexual yam, Dioscorea melanophyma, produces berry-like bulbils that trick birds into dispersing vegetative clones; birds perceive bulbils as real fruit, enabling endozoochory-based spread with a median distance of about 230 meters and occasional transfers beyond 500 meters, helping seedless plants expand without seeds.
Charlotte, a stingray in a North Carolina aquarium, is pregnant despite not having been with a male for at least eight years. The pregnancy is likely due to parthenogenesis, a form of asexual reproduction where a female egg is fertilized without the sperm from a male. This phenomenon has been observed in some species like insects, reptiles, and fish. Charlotte could give birth to as many as four young in the next two weeks, and this is the only documented example of this species reproducing in this manner.
A female stingray at a North Carolina aquarium is pregnant despite the absence of a male mate, prompting speculation about the cause. The aquarium is considering two possibilities: a rare form of asexual reproduction called parthenogenesis, or potential impregnation by a male shark. An ultrasound revealed that the swelling in the stingray's body was actually eggs, and bite marks on the stingray suggested mating behavior. The aquarium is awaiting the birth of the pups to confirm the cause of the pregnancy.
Stick insects in the genus Timema, known for their asexual reproduction, have been found to occasionally engage in sexual reproduction, challenging the assumption that they are completely asexual. Researchers studying four asexual Timema species discovered that these insects have managed to maintain their populations without sex for millions of years, but occasionally introduce genetic diversity through rare instances of sexual reproduction. Asexual reproduction offers advantages such as ease of reproduction and resilience after environmental disturbances, but the ability to occasionally have sex allows for genetic rejuvenation. This finding highlights the complexity of biological categorizations and the need for comprehensive evaluation before concluding an organism's reproductive strategy.
An 18-year-old American crocodile in a Costa Rican zoo impregnated herself through a form of asexual reproduction called facultative parthenogenesis, according to research published Wednesday. While other animals have reproduced through parthenogenesis, it was the first known case involving a crocodile. The stillborn crocodile was a genetic match solely to its mother, meaning that the adult crocodile impregnated herself. The International Union for Conservation of Nature lists American crocodiles as a vulnerable species.
A female crocodile in a Costa Rican zoo, who had been living alone for 16 years, laid eggs that resulted in a stillborn crocodile. Researchers discovered that the baby crocodile was a parthenogen, a form of asexual reproduction in which an embryo develops from an unfertilized egg cell. This is the first time it’s been found in crocodiles, and it is likely that dinosaurs and pterosaurs also produced offspring via parthenogen. The discovery and analysis make it very likely that parthenogenesis occurred in the archosaurs group of vertebrates.
Researchers have reported the first-ever virgin birth in crocodiles, where an 18-year-old crocodile living alone laid 14 eggs through asexual reproduction. However, none of the eggs hatched, and only seven appeared to be fertile. One egg contained a stillborn fetus that lacked paternal genes, confirming the virgin birth hypothesis. The researchers opened up the eggs to study them more closely and found that the offspring had identical genotypes to the mother at greater than 99.9% of her homozygous loci, demonstrating a lack of paternal alleles.