A curved “hitchhiker’s thumb” is recessive to a straight thumb. The following...

1. A curved “hitchhiker’s thumb” is recessive to a straight thumb. The following pedigree traces the presence of hitchhiker’s thumb in a family. Identify the genotypes of all the people shown in the following pedigree chart. Enter genotypes as SS, Ss, ss and uncertain genotypes as S_. 3 marks

I-1 is _______    I-2 is ________

II-1 is _______  II-2 is ________   II-3 is _______  II-4 is ______

III-1 is _____   III-2 is _______   III-3 is _______ 

IV-1 is _____  IV-2 is _______   IV-3 is _______  IV-4 is ______



2. This pedigree traces tongue rolling in a family. Filled in circles and squares represent the ability to roll the tongue. The ability to roll your tongue is controlled by a dominant allele; people with the recessive allele cannot roll their tongue. Identify the phenotypes and genotypes of all the people shown in this pedigree. Enter phenotypes as roll or not. Enter gentoypes as RR, Rr or rr. 6 marks


I-1 phenotype___ and genotype is ____  I-2 phenotype ___ and genotype is ___

II-1 phenotype___ and genotype is ___ II-2 phenotype ___ and genotype is ___ II-3 phenotype___ and genotype is ___ II-4 phenotype ___ and genotype is ___

III-1 to III-5 find phenotype and genotype

Post Merge: 7 years ago

Picture on the right is for question 1 and picture on left is for question 2