منابع مشابه
Problems of Birds Sex Determination
Sex determination system in birds is characterized by a homo-(Neognatae) and heteromorphic (Paleognatae) sex chromosomes. Heterogametic sex is female (ZZ/ZW system). DMRT1 gene is a gene regarded as a main male sex determining factor in this group of animals. The question remains about the participation of other factors (HEMOGEN, AMH etc.) in appearance of testis, and the role of steroid hormon...
متن کاملGonadal asymmetry and sex determination in birds.
Although vertebrates display a superficial bilateral symmetry, most internal organs develop and locate with a consistent left:right asymmetry. There is still considerable debate as to when this process actually begins, but it seems that, at least for some species, the initial steps occur at a very early stage of development. In recent years, a number of model systems, including the chick embryo...
متن کاملSex determination in birds: HINTs from the W sex chromosome?
Sex in birds is controlled genetically (ZZ male: ZW female), but the genetic mechanism remains unclear. While some evidence points to the involvement of Z sex chromosome dosage, other data favour a dominant female-determining gene carried on the W sex chromosome. An intriguing candidate gene located on the chicken W chromosome is HINTW, which encodes an aberrant form of a hydrolase enzyme. In c...
متن کاملReview. Meiotic drive and sex determination: molecular and cytological mechanisms of sex ratio adjustment in birds.
Differences in relative fitness of male and female offspring across ecological and social environments should favour the evolution of sex-determining mechanisms that enable adjustment of brood sex ratio to the context of breeding. Despite the expectation that genetic sex determination should not produce consistent bias in primary sex ratios, extensive and adaptive modifications of offspring sex...
متن کاملMeiotic drive and sex determination: molecular and cytological mechanisms of sex ratio adjustment in birds
Differences in relative fitness of male and female offspring across ecological and social environments should favour the evolution of sex-determining mechanisms that enable adjustment of brood sex ratio to the context of breeding. Despite the expectation that genetic sex determination should not produce consistent bias in primary sex ratios, extensive and adaptive modifications of offspring sex...
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ژورنال
عنوان ژورنال: Natural Science
سال: 2014
ISSN: 2150-4091,2150-4105
DOI: 10.4236/ns.2014.615111