Science Class- Mar 3-6

This week, we looked at some of the traits we have.  From a list of traits, we marked the traits we do and don't have.  We looked at the results from everyone and tried to figure out which were dominant or recessive based on the number of people that had it.  The traits are: tongue rolling (dominant), widow's peak (dominant), dimples (dominant), earlobe attachment (recessive), mid-digit hair (I think dominant), PTC taster (dominant), and cleft chin (recessive).  

If someone shows a dominant trait, you cannot tell if they are heterozygous because you only see the dominant trait.   You can probably tell by looking at the children or family members, but you can't tell from just looking at someone.  If someone shows a recessive trait, you know they are not heterozygous because both alleles would have to be recessive.  

We also did a lab that has to do with Punnett Squares and actual traits.  For the lab, we made up traits and whether they were dominant or not.  Then, in our groups, we made genotypes for the trait a set of parents.  We made Punnett Squares to predict  if the child would have the trait or not.  We had papers with alleles for the mom and dad that we put in a jar, and we picked an allele from each.  We made four genotypes for the kid's trait.  Most of the time, the traits we picked were different from on the Punnett Square.  The Punnett Square isn't always right about exactly what child would have which trait.  They just tell you the possible genotypes and the chances that the child would end up with it.