Discussion:
Genotyping and Phenotyping Traits
1. Would the person who could roll his/her tongue know their genotype for certain? Why?
2. What might determine whether a person who shows the dominate characteristic is homozygous dominant or heterozygous?
3. Now, knowing the details of red-green deficiency, please explain why males tend to show sex-linked traits more than females? Can you think of any other sex-linked traits?
4. Need to do a table with the following information by titles:
Trait, Possible Phenotype, Sample size of one or two family members or co-workers, Determine each person's Dominant #, Recessive # Personal Phenotype, Possible Genotype
Categories are:
Tongue Rolling T or t Thumb crossing C or c Handedness R or r Chin Dimple K or k
Widow's Peak W or w Mid-digit Hair M or m Toe Length S or s Freckles F or f
Detached Earlobes E or e Hitch-hikers thumb H or h Cheek Dimple D or d Iris Pigment I or i
5. If you do not show the trait write the representative lower case letter in the phenotype space. If you do not show the trait you can also be certain your genotype may be a homozygous recessive condition represented by two small letters. Write your genotype for each trait.
6. If you show the trait, write XX and Xx in the spaces above since you do not know for certain which set of alleles you possess