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The XY sex-determination systemis a sex-determination systempresent in many mammals, including humans, some insects (Drosophila), some snakes, some fish (guppies), and some plants (Ginkgotree). In this system, the sexof an individual usually is determined by a pair of sex chromosomes. Typically, females have two of the same kind of sex ...
Sex-determination system. Some chromosomal sex determination systems in animals. A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. [1] Most organisms that create their offspring using sexual reproduction have two common sexes and a few less common intersex variations.
Sex chromosomes (also referred to as allosomes, heterotypical chromosome, gonosomes, heterochromosomes, [ 1 ][ 2 ] or idiochromosomes[ 1 ]) are chromosomes that carry the genes that determine the sex of an individual. The human sex chromosomes are a typical pair of mammal allosomes. They differ from autosomes in form, size, and behavior.
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] The sex chromosome in a human egg is always an X chromosome since a female only has X sex chromosomes.
The X chromosome is one of the two sex chromosomes in many organisms, including mammals, and is found in both males and females. It is a part of the XY sex-determination system and XO sex-determination system. The X chromosome was named for its unique properties by early researchers, which resulted in the naming of its counterpart Y chromosome ...
In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also known as the SRY gene. [5] Thus, male mammals typically have an X and a Y chromosome (XY), while female mammals typically have two X chromosomes (XX).
Other organisms have mirror image sex chromosomes: where the homogeneous sex is the male, with two Z chromosomes, and the female is the heterogeneous sex with a Z chromosome and a W chromosome. [48] For example, the ZW sex-determination system is found in birds , snakes , and butterflies ; the females have ZW sex chromosomes, and males have ZZ ...
Intersex people are born with sex characteristics (including genitals, gonads and chromosome patterns) that do not fit typical binary notions of male or female bodies. Intersex is an umbrella term used to describe a wide range of natural bodily variations. [2] Attitudes towards the term.