¶ … Genetic Trait Phonotypes in My Family

The traits selected for this three-generation pedigree are freckles and hair texture. Freckles and curly hair show up as both recessive traits and dominant traits in my family. In the pedigree chart below, circles indicate female members of the family while males are indicated by squares. In the generations following my great grandparents, the symbols (circles, squares) that are red in color indicate the direct bloodline to me. The designations used in the pedigree chart for the dominant and recessive traits are as follows:

Freckles / FF = present; Ff = present; ff = absent

Hair texture / HH = curly; Hh = wavy; hh = straight

In scientific terms these relationships are described as:

dominant allele + dominant allele = dominant phenotype dominant allele + recessive allele = dominant phenotype recessive allele + recessive allele = recessive phenotype ("Utah," 2015)

The expression of the traits for freckles and curly hair texture in my family is interesting because it shows a preponderance of freckles and curly hair, almost as though earlier generations of my family preferred members of the opposite sex with freckles and curly hair. Perhaps, in the community in which my great grandparents and grandparents lived, there was a disproportionate number of people with freckles and curly hair. Or at least, in the backward looking examination of the presence or absence of the traits, the presence of freckles and curly hair tipped the scales for an eventual marriage. It would have been interesting to add a third trait, such as hair color, to this pedigree to see if freckles were more associated with red hair, or if curly hair was more often associated with red hair than was straight hair. Since the curly hair trait is dominant over straight hair trait, and since the freckles trait is dominant over the non-freckles trait, it is not surprising that so many of the offspring in this family pedigree chart are show a dominant phenotype.

References

University of Utah, Health Sciences. (2015). What are Dominant and Recessive? Retrieved from http://learn.genetics.utah.edu/content/inheritance/patterns/

Freckles / FF = present; Ff = present; ff = absent

Hair texture / HH = curly; Hh = wavy; hh = straight

FF

HH

ff hh

Ff

Hh

FF

HH

Great grandparents

Ff

hh

Ff

HH

FF

HH

Ff

Hh

Grandparents

FF

HH

Ff

hh

FF

HH

FF

Hh

Ff

hh

Ff

Hh

FF

HH

Parents

Me

Screenshot (in case figures move around)