Thursday, April 21, 2011

My Family's Genetics

Tongue Rolling
In biology, we tested multiple genetic traits on our families, to see if our parents (and in some cases ourselves) were Homozygous Dominant, Heterozygous or Homozygous Recessive. When we asked our family, we tested on the following traits:

1) Tongue Rolling
2) Attached Earlobes
3) Hitch Hiker's Thumbs
Attached Earlobes (bottom)

4) Widow's Peak

When I asked my mom, my dad and my sister, I found the following chart:
(+ if yes, can do it/has it, - if not)
                       Family Genetics
Trait                Mom      Dad     Phoebe     Megan

Hitch Hiker's Thumb
Tongue Rolling          +         +         +           +

Attached Earlobe        -         -          -           -

H.H. Thumb             +        +          +           +

Widow's Peak          -        -          -            -

As you can see, from this chart, all of the traits that we tested were the same throughout my family. This is interesting because we are all the same, and because my mom and dad shared the same trait, because of genetics and we (my sister and I) being their children, we automatically would share that same trait.

From a source, I found the following data about if these four traits were dominant or recessive:

1) Being able to roll your tongue: Dominant
2) Having attached earlobes: Recessive
3) Having a hitch hiker's thumb: Recessive
4) Widow's peak: Dominant

Because of this and from the data that I collected from my family I can determine the following:
- For tongue rolling, because it is dominant and both of my parents can roll their tongue, they are either homozygous dominant (RR) or heterozygous (Rr), we cannot confirm that from just this data.
- For earlobes, because having an unattached earlobe is dominant, both of my parents have unattached earlobes, they must be either homozygous dominant or heterozygous.
- Having a hitch hiker's thumb is recessive, of which both of my parents have. Because both of their children have a hitch hikers thumb both must be homozygous recessive (rr), because if one had a dominant gene in them, one of their offspring would not have a hitch hiker's thumb
- Having a widow's peak is dominant, and because both of my parents don't have a widow's peak, they must be homozygous recessive.

From this data we can conclude for sure if a parent is homozygous recessive, but not the difference between homozygous dominant and heterozygous. This is because you only need one dominant pairing for a person to have that trait, so, the person could show the trait and be Rr or RR, you simply don't know until you have kids, of which if one doesn't show the trait, you know you are Rr. This is not the case for my family, because when my parents had a trait, me and my sister would both have the trait, thus determining that we can't tell whether my parents are Rr or RR.

For more information on dominant vs. recessive genes see this link:

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