Do differences in Toxoplasma prevalence influence global variation in secondary sex ratio? Preliminary ecological regression study
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چکیده
منابع مشابه
Do differences in Toxoplasma prevalence influence global variation in secondary sex ratio? Preliminary ecological regression study.
Sex of the fetus is genetically determined such that an equal number of sons and daughters are born in large populations. However, the ratio of female to male births across human populations varies significantly. Many factors have been implicated in this. The theory that natural selection should favour female offspring under suboptimal environmental conditions implies that pathogens may affect ...
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Within the area of sex allocation, one of the topics that has attracted a lot of attention is the sex ratio problem. Fisher (1930) proposed that equal numbers of males and females have been promoted by natural selection and it has an adaptive significance. But the empirical success of Fisher's theory remains doubtful because a sex ratio of 0.50 is also expected from the chromosomal mechanism of...
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Analysis of the effect of multiple birth, birth order, age of parents and the sexes of preceding siblings on the secondary sex ratio was performed for 815 891 children, born in Denmark, 1980-1993. The proportion of males was analysed as a function of multiple birth, birth order, age of parents and the sexes of preceding siblings, using contingency tables, chi(2) tests and logistic regression an...
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BACKGROUND: The parasitic protozoa Toxoplasma gondii is widely prevalent in humans and warm-blooded animals. Humans are usually infected with T. gondii by ingesting oocysts shed by cats or by ingesting viable tissue cysts present in raw or undercooked meat. OBJECTIVES: This preliminary study was conducted to assess the frequency of Toxoplasma gondii infection in tissue samples of ewes slaughter...
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ژورنال
عنوان ژورنال: Parasitology
سال: 2016
ISSN: 0031-1820,1469-8161
DOI: 10.1017/s0031182016000597