An individual may have two similar alleles or two different alleles. If the individual has two similar alleles, the gene is homozygote. If the individual has two different alleles, the gene is heterozygote. A homozygote individual can only give one type of allel to its offspring while a heterozygote individual could give any one of the two types of alleles to its offspring.
An example of how an offspring’s sex is determined: The male carries one X
chromosome and one Y
chromosome, while the female carries two X
chromosomes. The female can therefore only give X
to the offspring whereas the male can give either X
- If the male gives an X, the offspring is X/X = female.
- If the male gives a Y, the offspring is X/Y = male.