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The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
Whilst XY sex determination is the most familiar, since it is the system that humans use, there are a range of alternative systems found in nature. The inverse of the XY system (called ZW to distinguish it) is used in birds and many insects, in which it is the females that are heterogametic (ZW), while males are homogametic (ZZ). [18]
Some species (including humans) have a gene SRY on the Y chromosome that determines maleness. Members of SRY-reliant species can have uncommon XY chromosomal combinations such as XXY and still live. [9] Human sex is determined by the presence or absence of a Y chromosome with a functional SRY gene.
Sexual size dimorphism varies among taxa, with males typically being larger, though this is not always the case, e.g. birds of prey, hummingbirds, and some species of flightless birds. [ 67 ] [ 68 ] Plumage dimorphism, in the form of ornamentation or coloration, also varies, though males are typically the more ornamented or brightly colored sex ...
A human egg contains only one set of chromosomes (23) and is a haploid. Sperm also have only one set of 23 chromosomes and are therefore haploid. When an egg and sperm fuse at fertilization, the two sets of chromosomes come together to form a unique diploid individual with 46 chromosomes. [2]
“Gender identity is how you feel about yourself and the ways you express your gender and biological sex,” says Golob. Meanwhile, sexuality refers to who you are emotionally, physically ...
Gender-based medicine, also called "gender medicine", is the field of medicine that studies the biological and physiological differences between the human sexes and how that affects differences in disease. Traditionally, medical research has mostly been conducted using the male body as the basis for clinical studies.
The human Y chromosome showing the SRY gene which codes for a protein regulating sexual differentiation. Sexual differentiation in humans is the process of development of sex differences in humans. It is defined as the development of phenotypic structures consequent to the action of hormones produced following gonadal determination. [1]