1. A) 5 family members have dimples (individuals 1, 2, 9, 10, 12, 14).
B) The genotype of individual #3 is Dd, and the genotype of individual #4 is Dd.
C) Individual #8 cannot be homozygous because they have a child (individual #12) with no dimples, which means they must carry the recessive allele (d). Individual #9 can be homozygous (DD) or heterozygous (Dd) because they have a child (individual #14) with no dimples, so they must carry the recessive allele (d), making them heterozygous (Dd).
D) #12 has dimples, so they must have at least one dominant allele (D). Since #12's parents (individuals #8 and #9) both have dimples but have a child without dimples (#12's sibling #13), both parents must be heterozygous (Dd). Therefore, #12 could be either DD or Dd. However, since #12 has dimples, they must have at least one D allele. The most likely genotype for #12 is Dd, as they could have inherited the D allele from one parent and the d allele from the other.
2. A) 2 family members have unibrows (individuals 1 and 4).
B) The genotype of individual #1 is ee, and the genotype of individual #2 is Ee.
C) Individual #3 can be homozygous (EE) or heterozygous (Ee) because they have a child (individual #10) with unibrows, which means they must carry the recessive allele (e), making them heterozygous (Ee). Individual #4 must be homozygous recessive (ee) because they have unibrows.
D) #12 has two eyebrows, so they must have at least one dominant allele (E). Since #12's parents (individuals #3 and #4) have a child (individual #16) with unibrows, #3 must be heterozygous (Ee) and #4 must be homozygous recessive (ee). Therefore, #12 could be either EE or Ee. However, since #12 has two eyebrows, they must have at least one E allele. The most likely genotype for #12 is Ee, as they could have inherited the E allele from one parent and the e allele from the other.
Parent Tip: Review the logic above to help your child master the concept of genetic pedigree worksheet.
