How to take Viagra. Viagra works best if it s taken approximately one hour before sexual activity. To get an erection, you will need to be sexually stimulated. Doctors usually recommend taking 50 mg once per day, but the dosage can be decreased to 25 mg or increased to 100 mg if needed.
Recessive allele: an allele that only has an effect on the phenotype when present in the homozygous state. Codominant alleles: pairs of alleles that both affect the phenotype when present in a heterozygote. Locus: the particular position on homologous chromosomes of a gene.Homozygous: having two identical alleles of a gene. Heterozygous: having two different alleles of a gene. Carrier: an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele.ocus: the particular position on homologous chromosomes of a gene. Homozygous: having two identical alleles of a gene. Heterozygous: having two different alleles of a gene. Carrier: an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele.
Recessive and dominant alleles. You will recall that genes have different forms called alleles. An allele can be recessive or dominant. A recessive allele only shows if the individual has two copies of the recessive allele. For example, the allele for blue eyes is recessive.You need two copies of the allele to have blue eyes. A dominant allele always shows, even if the individual only has one copy of the allele. For example, the allele for brown eyes is dominant.You only need one copy of the allele to have brown eyes (and two copies will still give you brown eyes).or example, the allele for blue eyes is recessive. You need two copies of the allele to have blue eyes. A dominant allele always shows, even if the individual only has one copy of the allele.