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.
4. According to the figure, how many of the grandchildren of Individual 1 and Individual 2, if any, have Trait G ?
Your Answer is
Correct Answer is H
Explanation
The third line is the grandchildren of No. 1 and No. 2, of which No. 10 and No. 16 have Trait G (No. 9 cannot be counted, because No. 9 is a grandson-in-law and a foreigner), so there are two grandchildren with Trait G