Pedigrees and Fainting Goats - Isn't Bio Fun?!?!

Today we started with another daily question that deals with Pedigrees

Using the following pedigree answer the questions below

1st: How many childred did the FIRST set of parents have? How many boys/girls?

The first set of parents had two kids - one boy and one girl.

Of those Children, which child had children of their own? (The boy or girl)

The BOY

How many boys/girls did He have? 3 boys and 1 girl

Based on this pedigree, the trait that is being seen must be dominant or recessive?

It must be recessive, how do i know this? A trait that shows up in children that is NOT expressed in either parent MUST be recessive. If this was a DOMINANT trait - at least ONE of the parents would have to also express it.

Because of this (the fact that it is recessive), what can we say about the genotypes of teh first and second set of parents?

Both of them would have to be carriers of the trait (so you would fill them in half way)

After this we analzyed another pedigree (handout - please see edline for the document if you missed it, or get it from me) This allowed us to determine genotypes of parents based on their offpsrings phenotypes.

We will now be moving in to more complex forms of heredity. MOST of our traits are not simple dominant or recessive. So simple Punnett squares are not very valuable for the majority of our traits. To START this off though we watched the "fainting goat video" (see blog above) then moved on in our notes to complex forms of inheritance. (Please check edline for notes if you missed)