Science Class- Mar. 9-13

This week, we learned about co dominance and incomplete dominance.  Incomplete dominance is when one allele is not completely dominant, so some of the recessive shows through.  An example of this is a red flower and a white flower having a pink flower.  Co dominance is when there are two equally dominant alleles.

Blood type is an example of co dominance.  Both A and B are dominant and o is recessive.  For blood type, they represent alleles with "I".  A is I with an A at the top, and B is an I with a B at the top.  O is just i.  The blood type A could be IA IA or IA i.  B could be IB IB or IB i.  AB would be IA IB.  O is i i.  Blood also has the Rh factor.  That means it can be positive or negative.  The + is dominant and the - is recessive.  

On Friday, we received traits for our make-believe bug selves.  We traced the bugs to make them look how they were supposed to.

We also learned how to make a dihybrid chart.  It shows the possible genotypes for two traits.  On the top and side are the possible allele combinations for the parents.  Here is an example for blood type with the Rh factor:

IA IB --,  IB i +-   Combinations: IA-, IB-, IA-, IB-;  IB+, i+, IB-, i- 

	IA -	IB -	IA -	IB -
IB +	IA IB +-	IB IB +-	IA IB +-	IB IB +-
i +	IA i +-	IB i +-	IA i +-	IB i +-
IB -	IA IB --	IB IB --	IA IB --	IB IB --
i -	IA i --	IB i --	IA i --	IB i --