how is sex determined and inherited
Answer (1)
Answer:Sex determination and inheritance are complex processes, varying across species. However, in humans and many other mammals, the primary mechanism is as follows: Sex Determination: - Chromosomes: Humans have 23 pairs of chromosomes, with one pair determining sex. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY).- Y Chromosome's Role: The Y chromosome carries the SRY gene (sex-determining region Y). This gene triggers the development of testes in the embryo. Testes then produce testosterone, which leads to the development of male characteristics. Without the SRY gene (as in XX individuals), the embryo develops ovaries and female characteristics. Sex Inheritance: - Parental Contribution: Each parent contributes one sex chromosome to their offspring. The mother always contributes an X chromosome (from her XX pair). The father can contribute either an X or a Y chromosome (from his XY pair).- Probability: This results in a roughly 50% chance of a child inheriting an XX combination (female) and a 50% chance of inheriting an XY combination (male).- Other Factors: While the chromosomal mechanism is the primary determinant, other genes and environmental factors can influence sexual development and characteristics. These are less common and often result in variations from the typical XX/XY pattern. Examples include:- Intersex conditions: These are variations in sex characteristics that don't fit the typical definitions of male or female. They can be caused by genetic or hormonal factors.- Environmental sex determination: In some species, environmental factors like temperature can determine the sex of the offspring. In Summary: Sex in humans is primarily determined by the presence or absence of the Y chromosome and the SRY gene. This genetic information is inherited from both parents, with the father's contribution determining whether the offspring will be male (XY) or female (XX). However, it's crucial to remember that biological sex is a spectrum, and variations from the typical XX/XY pattern are possible.
