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XX Chromosome
The XY sex-determination system is a sex-determination system used to classify many mammals, including humans, some insects (''Drosophila''), some snakes, some fish (guppies), and some plants (''Ginkgo'' tree). In this system, the sex of an individual is determined by a pair of sex chromosomes. Females have two of the same kind of sex chromosome (XX), and are called the homogametic sex. Males have two different kinds of sex chromosomes (XY), and are called the heterogametic sex. In humans, the presence of the Y chromosome is responsible for triggering male development; in the absence of the Y chromosome, the fetus will undergo female development. There are various exceptions, such as individuals with Klinefelter syndrome (who have XXY chromosomes), Swyer syndrome (women with XY chromosomes), and XX male syndrome (men with XX chromosomes), however these exceptions are rare. In most species with XY sex determination, an organism must have at least one X chromosome in order to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila XY Sex-determination
''Drosophila'' () is a genus of fly, flies, belonging to the family (biology), family Drosophilidae, whose members are often called "small fruit flies" or (less frequently) pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, ''Drosophila melanogaster, D. melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literature. The entire genus, however, contains more than 1,500 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
