heterogametic การใช้

• Haldane's rule applies to the vast majority of heterogametic organisms.
• Males are the homogametic sex ( ZZ ), while females are the heterogametic sex ( ZW ).
• Haldane's rule states that if in a species sterile, that sex is usually the heterogametic sex.
• Because the male Savannah is the heterogametic sex, they are most commonly affected, in accordance with Haldane's rule.
• Many butterflies are ZW sex-determination system where females are the heterogametic sex ( ZW ) and males homogametic ( ZZ ).
• The heterogametic sex is the one with two different sex chromosomes; in mammals, this is the male, with XY chromosomes.
• Thus, heterogametic male organisms with one X chromosome may match the level of expression achieved in homogametic females with two active X chromosomes.
• Among the insects, Lepidopterans ( butterflies and moths ) have heterogametic females, but in " Drosophila ", males are the heterogametic sex.
• Among the insects, Lepidopterans ( butterflies and moths ) have heterogametic females, but in " Drosophila ", males are the heterogametic sex.
• This could cause the heterogametic sex chromosome in the hybrid to be inviable or sterile, but homogametic sex chromosome will be fertile ( Futuyma 1997 ).
• In ZW sex-determination system used by birds the opposite is true : the male is the homogametic sex ( ZZ ), and the female is heterogametic ( ZW ).
• Alternatively, birds might show decreased transcription of the two Z chromosomes present in the male heterogametic sex, similar to the system observed in the two male X chromosomes of Drosophila.
• This system is in contrast with the ZW sex-determination system found in birds, some insects, many reptiles, and other animals, in which the heterogametic sex is female.
• The heterogametic sex ( males in humans ) only receives one of each sex chromosome and will therefore show recessive trait even if they have only inherited one copy of a recessive allele.
• In mammals, the female is homogametic, with two X chromosomes ( XX ), while the male is the heterogametic sex, with one X and one Y chromosome ( XY ).
• However, in birds, and some reptiles, males have two Z sex chromosomes and so are the homogametic sex, while females, with one Z and one W chromosome, are the heterogametic sex.
• This happens because female birds have a single Z sexual chromosome, while males carry two, contrarily to what happens in humans, where the male is the heterogametic sex, as occurs in most diploid species.
• Birds and many insects have a similar system of sex determination ( " ZW sex-determination system " ), in which it is the females that are heterogametic ( ZW ), while males are homogametic ( ZZ ).
• For example, in humans, males, with an Y sex chromosome, would be referred to as the heterogametic sex, and females having two X sex chromosomes would be referred to as the "'homogametic sex " '.
• Normal females are always of genotype " Dw /-", while dwarf females are always of genotype " dw /-", because female is the heterogametic sex having only one " Z " chromosome.