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  2. Sex-determination system - Wikipedia

    en.wikipedia.org/wiki/Sex-determination_system

    For example, there are moths and butterflies that are ZW, but some have been found female with ZO, as well as female with ZZW. [22] Also, while mammals deactivate one of their extra X chromosomes when female, it appears that in the case of Lepidoptera , the males produce double the normal amount of enzymes, due to having two Z's. [ 22 ]

  3. Major histocompatibility complex and sexual selection

    en.wikipedia.org/wiki/Major_histocompatibility...

    MHC-based sexual selection is known to involve olfactory mechanisms in such vertebrate taxa as fish, mice, humans, primates, birds, and reptiles. [1] At its simplest level, humans have long been acquainted with the sense of olfaction for its use in determining the pleasantness or the unpleasantness of one's resources, food, etc.

  4. Sex differences in human physiology - Wikipedia

    en.wikipedia.org/wiki/Sex_differences_in_human...

    Sex differences in human physiology are distinctions of physiological characteristics associated with either male or female humans. These differences are caused by the effects of the different sex chromosome complement in males and females, and differential exposure to gonadal sex hormones during development.

  5. XY sex-determination system - Wikipedia

    en.wikipedia.org/wiki/XY_sex-determination_system

    Offspring have two sex chromosomes: an offspring with two X chromosomes (XX) will develop female characteristics, and an offspring with an X and a Y chromosome (XY) will develop male characteristics, except in various exceptions such as individuals with Swyer syndrome, that have XY chromosomes and a female phenotype, and de la Chapelle Syndrome ...

  6. Zygosity - Wikipedia

    en.wikipedia.org/wiki/Zygosity

    Homozygous and heterozygous. Zygosity (the noun, zygote, is from the Greek zygotos "yoked," from zygon "yoke") (/ z aɪ ˈ ɡ ɒ s ɪ t i /) is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism.

  7. Maternal effect - Wikipedia

    en.wikipedia.org/wiki/Maternal_effect

    In genetics, a maternal effect occurs when the phenotype of an organism is determined by the genotype of its mother. [1] For example, if a mutation is maternal effect recessive, then a female homozygous for the mutation may appear phenotypically normal, however her offspring will show the mutant phenotype, even if they are heterozygous for the mutation.

  8. Sex differences in humans - Wikipedia

    en.wikipedia.org/wiki/Sex_differences_in_humans

    For example, on average, the SDN (INAH3 in humans) has been repeatedly found to be considerably larger in males than in females. [12] A brain study done by the NIH showed that the females had greater volume in the prefrontal cortex, orbitofrontal cortex, superior temporal cortex, lateral parietal cortex, and insula, whereas males had greater ...

  9. Heterozygote advantage - Wikipedia

    en.wikipedia.org/wiki/Heterozygote_advantage

    Multiple studies have shown, in double-blind experiments, females prefer the scent of males who are heterozygous at all three MHC loci. [ 21 ] [ 22 ] The reasons proposed for these findings are speculative; however, it has been argued that heterozygosity at MHC loci results in more alleles to fight against a wider variety of diseases, possibly ...