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.
Alleles are dominant or recessive, meaning: 1  the characteristic controlled by a dominant allele develops if the allele is present on one or both chromosomes in a pair. 2  the characteristic controlled by a recessive allele develops only if the allele is present on both chromosomes in a pair.lleles are dominant or recessive, meaning: 1  the characteristic controlled by a dominant allele develops if the allele is present on one or both chromosomes in a pair. 2  the characteristic controlled by a recessive allele develops only if the allele is present on both chromosomes in a pair.