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The XY sex-determination system is a sex-determination system present in many mammals, including humans, some insects (Drosophila), some snakes, some fish (guppies), and some plants (Ginkgo tree). In this system, the sex of an individual usually is determined by a pair of sex chromosomes. Typically, females have two of the same kind of sex ...
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. Sexual dimorphism is a term for the ...
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.
Karyotype. A karyotype is the general appearance of the complete set of chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. [1][2] Karyotyping is the process by which a karyotype is discerned by determining the chromosome complement of an individual, including the number of ...
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).
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 differences in humans have been studied in a variety of fields. Sex determination generally occurs by the presence or absence of a Y chromosome in the 23rd pair of chromosomes in the human genome. Phenotypic sex refers to an individual's sex as determined by their internal and external genitalia and expression of secondary sex characteristics.
Chromosomal changes during the cell cycle are displayed at top center. The mitochondrial genome is shown to scale at bottom left. The human genome is a complete set of nucleic acid sequences for humans, encoded as the DNA within each of the 24 distinct chromosomes in the cell nucleus. A small DNA molecule is found within individual mitochondria.