In this paper, we suggest an alternative mechanism based on the failure of polar body emission, followed by fertilization of multiple haploid nuclei through polyspermy and subsequent competition of Z and W bearing cells within chimeric embryos.
Although the occurrence of failure of polar body extrusion is obvious from the observations of chimeric birds, the idea that it could be the first step of offspring sex ratio bias has been entirely overlooked.
We review the evidence in support of that idea, demonstrate that it is consistent with the observations of biased offspring sex ratio reported so far, and suggest a way to verify it.
Relative costs and benefits of producing sons and daughters differ across ecological and social environments.
Our hypothesis is based on the PB and a pronucleus nuclei developmental equipotential.
This is theoretically expected from the molecular basis of chromosomal DNA separation during cell splitting, and an experimentally proven fact (Wakayama and Yanagimachi 1998). The second arguing point of our hypothesis is that it is based on the abnormality of an essential physiological process, extrusion of the PBs during meiosis.
Wearing white plastic masks, the protesters held placards reading "Sex work is work", "We stand for decriminalisation of sex work", and "My work is my choice"."It is the first time that we have had the courage to come out and say that we exist," Yuliya Dorokhova of Legalife.Valeria Costa-Kostritsky is a French journalist based in London.She writes about politics, women's rights and social issues for publications including L'Obs, the London Review of Books and Index on Censorship.The starting point for our hypothesis was an article by Zhao et al.(2010), where the authors, after comprehensive analysis of gynandromorphic chickens, concluded that “Our data establishing the presence of both ZZ- and ZW-containing cells indicate that it is highly unlikely that these birds arise as a consequence of mutation at the 2-cell stage of development, and would support the hypothesis that gynandromorphs arise as a result of failure of extrusion of a polar body (PB) during meiosis and subsequent fertilization of both a Z- and W-bearing female pronucleus” (Zhao et al. I acknowledge that we used this “accepted” idea originating from Hollander’s (1975) work to build our hypothesis.