What are examples of sex-linked genetic characteristics?

Sex-linked genetic characteristics include colour blindness, haemophilia, and Duchenne muscular dystrophy.

Sex-linked genetic characteristics are traits that are determined by genes located on the sex chromosomes. In humans, these are the X and Y chromosomes. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

Colour blindness is a common sex-linked characteristic. It is a condition that affects the ability to perceive different colours and is usually inherited. The genes responsible for this trait are located on the X chromosome. As males only have one X chromosome, if they inherit the gene for colour blindness, they will express the trait. However, females have two X chromosomes, so they would need to inherit the gene from both parents to express the trait. If they only inherit one gene, they become carriers and can pass it on to their offspring.

Haemophilia is another example of a sex-linked characteristic. It is a disorder that impairs the body's ability to make blood clots, leading to excessive bleeding. The gene for haemophilia is located on the X chromosome. Like colour blindness, males who inherit the gene will express the trait, while females can be carriers.

Duchenne muscular dystrophy is a severe type of muscular dystrophy, a group of genetic diseases that cause progressive weakness and loss of muscle mass. The gene for Duchenne muscular dystrophy is also located on the X chromosome, making it a sex-linked characteristic.

In summary, sex-linked genetic characteristics are determined by genes on the sex chromosomes. They include conditions such as colour blindness, haemophilia, and Duchenne muscular dystrophy. Understanding these traits can help in predicting the likelihood of their occurrence in offspring.