You can see from the Punnett square that three of the four gamete combinations will contain at least

You can see from the Punnett square that three of the four gamete combinations will contain at least

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
You can see from the Punnett square that three of the four gamete combinations will contain at least  one dominant allele (T) and that there is only one chance out of four that the recessive (t) can be  expressed. Mendel's experimental results fit the phenotypic probability ratio of 3:1. The genotypic  ratio, which Mendel didn't know about, is not 3:1, but 1:2:1. That is, 1 homozygous dominant (TT):2  heterozygous dominants (Tt):1 homozygous recessive (tt). The Punnett square shows only the  possible  combinations, not the actual. It provides an easy way to visualize the  probabilities  of a  certain combination occurring. In some inherited traits, whether the allele comes from the male or  the female parent can make a difference, but in most traits such information does not matter.  After making monohybrid crosses for all the traits and finding that the ratios always approximated 
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/14/2011 for the course BIO 1421 taught by Professor Farr during the Fall '08 term at Texas State.

Ask a homework question - tutors are online