Genetics Problems
      
                 
               
                 

Objectives for today:

* Use a Punnents square to determine probability of traits in offspring given traits of both the parents.

 
  Monohybrid Cross: a cross concerned with only one trait.    
                 
   

Monohybrid sample problem:

* In roses, red is dominant over white.
* Use R for the red gene.
* Use r for the white gene.
* Cross two heterozygous red roses, Rr X Rr

* From the Punnett Square,

* describe the phenotype of the offspring.

* 3/4 Red
* 1/4 White

* describe the genotype of the offspring.

* 1/4 RR
* 1/4 rr
* 1/2 Rr

     
   
     
       
 
   
 

Hear your paper Unit 4 Day 4 Punnent Square Practice.

Draw the Punnett Square required for each problem, then answer the questions about the offspring.

1. Monohybrid cross:
In certain trees, smooth bark is dominant over wrinkled. Cross two trees that are heterozygous for smooth bark. If there are 100 offspring produced, how many will have wrinkled bark?


2. Monohybrid cross:
In Mountain Boomers, the genes for length of tail exhibit "incomplete" dominance. Use a Punnett Square to predict the result of a cross between a homozygous Long-tailed and a homozygous Short-tailed Mountain Boomer. What do the offspring look like?