The XY sex-determination system is used to classify many mammals, including humans, some insects, some snakes, some fish, and some plants. The Y chromosome is one of two sex chromosomes in therian mammals and other organisms, and it is part of the XY sex-determination system. In mammals, the presence or absence of the Y chromosome determines the male or female sex of offspring produced in sexual reproduction. The Y chromosome contains the SRY gene, which triggers development of male gonads.
Some key points about the XY sex-determination system and the Y chromosome include:
- Males have two different kinds of sex chromosomes (XY), and are called the heterogametic sex.
- Females inherit an X chromosome from the father for an XX genotype, while males inherit a Y chromosome from the father for an XY genotype (mothers only pass on X chromosomes) .
- In most cases, the female is XX and the male is XY. Every individual must have at least one X chromosome.
- An individual with an X chromosome that carries the SRY gene will develop as a male despite not having a Y chromosome, but will not be able to produce sperm to father biological children.
- Some individuals have chromosomal abnormalities that affect the number or structure of their sex chromosomes, such as XXY (Klinefelter syndrome), XXX (Triple X syndrome), XYY syndrome, and XXYY syndrome.
In summary, the XY sex-determination system is a biological mechanism that determines the sex of many mammals, including humans, and the Y chromosome is one of two sex chromosomes in therian mammals and other organisms that plays a key role in this process.
