The MMR vaccine protects your child against three viruses: measles, mumps, and rubella (German measles). You can also protect your child against chicken pox with the MMRV vaccine. The MMRV is the same as the MMR, except that it also includes protection against the varicella virus, which causes chicken pox. Some parents get the first dose of the MMR vaccine for their child, and choose the MMRV vaccine for the second dose.
Rating Newest Oldest. Best Answer: Widows peak is caused by a dominant gene, say W. Let's assume the recessive straight hairline gene as w. In your case, your mom's widows peak gene is likely, Ww. Your dad's is ww. You need at least one W to have it expressed, but you need two ww to have straight hairline. Obviously, you inherit the w genes from both your parents, so you have straight hairline.
A dominant allele masks the expression of the recessive geneâs trait. The alleles are homozygous if they code for the same trait and heterozygous if they code for different traits. A homozygous pair might have two dominant or two recessive alleles. Dominant genes are indicated by capital letters, recessives by small letters. For example, P stands for round peas and w stands for the wrinkled variety. A heterozygous pea plant has the Pw allele pair, while a dominant homozygous plant has two dominant genes, PP. Both have round peas. Codominance. Animal scientists have identified the genes that give a horse a roan-colored coat as being codominant.