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Other species (including most Drosophila species) use the presence of two X chromosomes to determine femaleness: one X chromosome gives putative maleness, but the presence of Y chromosome genes is required for normal male development. In the fruit fly individuals with XY are male and individuals with XX are female; however, individuals with XXY ...
This ratio is used primarily for determining the sex of some species, such as drosophila flies and the C. elegans nematode. [1] The first use of this ratio for sex determination is ascribed to Victor M. Nigon. [1] Generally, a 1:1 ratio results in a female and a 1:2 ratio results in a male. When calculating the ratio, Y chromosomes are ignored.
For instance, in birds, male and female somatic cells may exhibit intrinsic differences due to CASI, but the extent to which these differences manifest in tissues can be influenced by circulating hormones such as estrogen and testosterone. Hormones act as amplifiers, enhancing or suppressing sex-specific characteristics that are intrinsically ...
The delay in effectiveness of the incapacitation mechanism is believed to be a protective mechanism that prevents a male fly from incapacitating his own sperm should he mate with the same female fly repetitively. Sensory neurons in the uterus of female D. melanogaster respond to a male protein, sex peptide, which is found in semen. [36]
A metamale (or supermale) is a low viability Drosophila fruit fly with a male phenotype in which the ratio of X chromosomes to sets of autosomes (A) is less than 0.5. [1] For example: a fly with one X chromosome and two sets of autosomes is a normal male, a fly with one X chromosome and three sets of autosomes is a metamale.
The gene is expressed in both male and female flies and is subject to alternative splicing, producing the protein isoforms dsx f in females and the longer dsx m in males. The production of dsx f is caused by the presence of the female-specific version of the transformer (tra) gene.
Drosophila is a prime candidate for genetic research because the relationship between human and fruit fly genes is very close; disease-producing genes in humans can be linked to those in Drosophila. [52] The fly has approximately 15,500 genes on its four chromosomes, whereas humans have about 22,000 genes among their 23 chromosomes. [53]
The term comes from the Greek γυνή (gynē) 'female', ἀνήρ (anēr) 'male', and μορφή (morphē) 'form', and is used mainly in the field of entomology. Gynandromorphism is most frequently recognized in organisms that have strong sexual dimorphism such as certain butterflies, spiders, and birds, but has been recognized in numerous ...