Question

Which one of the following statement is relevant to sex-linked characters?
A.They always follow criss cross inheritance.
B.They do not follow the criss cross inheritance
C.They are mostly present on the Y chromosome
D.They are only present on the X chromosome

Answer 1

Inheritance is the cycle by which characters are passed from parents to offspring. It is the premise of heredity. Variation is the degree by which progeny differ from their parents.

Complete answer:
We all know that a lioness will give birth to a lion, a dog will give birth to a dog, a bird will give birth to a bird and humans will only give birth to humans. But have you ever wondered why? Why is this thing only limited within their species? And this rule applies to plants also, mango seed will form mango plants only, not any other plant’s fruit. The answer to all these questions is inheritance.

Inheritance is the process of transfer of the parent gene to its offspring. And all these genes are present on the chromosomes. Even though the progeny is similar to the parents some characters are completely different from parents. Some characters are observable and some are not. Sex-linked character is an observable character and these characters are controlled genes present on the sex chromosome of each individual. An example of crisscross inheritance is- when a male has a defective sex-linked gene located on the X chromosome he transmits the defective X to the son and daughter. Both in equal probability as the female carries XX and male carries XY. The male passes on his recessives sex-linked trait 50% of his grandson through his daughter. Sex-linked characters follow criss-cross inheritance. Sex linkage and crisscross inheritance were first discovered by Thomas H. Morgan (father of modern genetics), in 1910 on Drosophila melanogaster. When the white-eyed male is crossed to normal red-eyed female, in the first generation all the males and females were red-eyed.

Hence, the correct answer is option (A)

Note: Now we know that in a crisscross type of inheritance father transmits its character to daughter and mother transmit its character to son. It is the transmission of a gene from mother to boy or father to a girl; for example in X-chromosome linkage.