NEET BIOLOGY

Detailed explanation-1: -Sex-linked traits are characteristics that are determined by genes located on the sex chromosomes. Inheritance patterns for these traits can differ for males and females, since the X and Y chromosomes differ. One example of a sex-linked trait is color blindness, which is primarily seen in males.

Detailed explanation-2: -This is why so many male-only diseases are attributable to defective genes on the X chromosome.” Such diseases include Duchenne muscular dystrophy, hemophilia and Hunter syndrome, which causes dwarfing, abnormal bones and mental retardation in males but usually does not affect females who carry the same mutated gene.

Detailed explanation-3: -A male is represented by a square or the symbol ♂, a female by a circle or the symbol ♀. Mating is shown by a horizontal line (marriage line) connecting a male symbol and a female symbol; offspring symbols are connected in a row (sibship line) beneath the mated pair.

Detailed explanation-4: -In the case of an X-linked disease, it is usually males that are affected because they have a single copy of the X chromosome that carries the disease-causing mutation. In females, the presence of a second, non-mutated copy may cause different, milder, or no symptoms of a sex-linked disorder.