Passage I

The figure below is a pedigree that shows the inheritance of a trait, Trait G, in a family. The presence of Trait G in an individual is determined entirely by Gene G. Gene G has 2 alleles: G, which is dominant, and g, which is recessive.

Each individual represented in the pedigree was assigned a number (shown below the symbol for the individual) for reference. Scientists determined that the Gene G genotype of Individual 20 is gg and that the Gene G genotype of Individual 21 is Gg. Based on this information, the scientists concluded that Trait G is a recessive trait.

3. Suppose that Individual 23 and Individual 24 have 4 biological children. Based on the figure, how many of the children, if any, have Trait G ?

Answer and Explanation

Your Answer is

Correct Answer is D

Explanation

It can be seen from the picture that Trait G is recessive inheritance, that is, gg (alternative inheritance is recessive, for example, No. 14 and No. 15 without Trait G can give birth to No. 22 and No. 23 of Trait G);

Both 23 and 24 have this feature, which means that their genotypes are both gg, that is to say, the genotype of their children must also be gg, so all children born will have this Trait G