Female cuckoos have two color variants: gray and rufous, linked to ancient mutations that emerged during the evolutionary arms race between host and cuckoo. The rarer color morph has an evolutionary advantage due to its rarity, causing genetic variation to be maintained for a long time.
Researchers have developed a method for sex-specific genetic engineering in silkworms, enabling the creation of fluorescent females for easy sex sorting. The technique uses a targeted gene integration approach that can be adapted for pest control by inducing female-specific embryonic lethality.
Researchers at Uppsala University mapped the genetic structure and evolution of the W chromosome in birds, finding that it does not contain genes leading to female development. The W chromosome instead serves as a buffer for females with one copy of the X chromosome, allowing certain genes to work.
Researchers have found that sex-linked chromosomes, particularly the W chromosome in female chickens, play a vital role in predicting fertility. The study's results support the idea that these chromosomes are unlikely to become extinct due to their importance in survival.