The probability of an F2 offspring having a green pod color and smooth pod shape is 9 out of 16, which is a combined probability of CCSS,CcSs, CCSs and CcSs.

Recessive inheritance means both genes in a pair must be abnormal to cause disease. People with only one defective gene in the pair are called carriers. These people are most often not affected with the condition. However, they can pass the abnormal gene to their children.

The Punnett square below makes it clear that at each birth, there will be a 25% chance of you having a normal homozygous (AA) child, a 50% chance of a healthy heterozygous (Aa) carrier child like you and your mate, and a 25% chance of a homozygous recessive (aa) child who probably will eventually die from this …

In addition, crossing two individuals that are both heterozygous will yield, on average, 50 percent heterozygous offspring; half of the remaining offspring, on average, will be homozygous for the dominant allele and half homozygous for the recessive allele.

As there is no second phenotype, there is no phenotypic ratio. If we did put this result as a ratio, it would be 4:0. The genotypic ratio, however, does not look at the observable trait (the phenotype) but at potential allele combinations.

As was mentioned by others, it is undefined. If you want the ratio “of A to B” then this means you want |A|/|B|. E.g. the ratio of Boys to Girls is the number of boys divided by the number of girls.

To identify whether an organism exhibiting a dominant trait is homozygous or heterozygous for a specific allele, a scientist can perform a test cross. The organism in question is crossed with an organism that is homozygous for the recessive trait, and the offspring of the test cross are examined.

Dominant traits are the most common traits in a population. When people hear the word “dominant”, often they incorrectly believe that the majority of the population expresses this trait. Describing a trait as dominant does not mean it is the most common; it means that it is expressed over the recessive trait.

Dominant traits are more frequent than the recessive ones. As the dominant gene mask or prevents the expression of the recessive gene.

The traits due to dominant alleles are always observed, even when a recessive allele is present. Traits due to recessive alleles are only observed when two recessive alleles are present. A widespread misconception is that traits due to dominant alleles are the most common in the population.

From this, people often jump to the conclusion that the dominant trait is also the most common one. Whether or not a trait is common has to do with how many copies of that gene version (or allele) are in the population. It has little or nothing to do with whether the trait is dominant or recessive.

Single Gene Traits