Back to Course

SS3: AGRICULTURAL SCIENCE - 1ST TERM

0% Complete
0/0 Steps
  1. Crop Improvement | Week 1
    9 Topics
    |
    1 Quiz
  2. Animal Improvement | Week 2
    6 Topics
    |
    1 Quiz
  3. Animal Health Management I - Introduction | Week 3
    7 Topics
    |
    1 Quiz
  4. Animal Health Management II | Week 4
    5 Topics
    |
    1 Quiz
  5. Animal Health Management III | Week 5
    7 Topics
    |
    1 Quiz
  6. Aquaculture | Week 6
    11 Topics
    |
    1 Quiz
  7. Apiculture or Bee-keeping | Week 7
    10 Topics
    |
    1 Quiz



Lesson 1, Topic 5
In Progress

Mendel’s Second Law (Law of Independent Assortment | Dihybrid Cross)

Lesson Progress
0% Complete

Topic Content:

  • Mendel’s Second Law (Law of Independent Assortment)
  • Describe a Dihybrid Cross Example in Pea Plants
  • Summary

What is Mendel’s Second Law?

Mendel’s Second Law – Law of Independent Assortment – states that when more than one pair of traits are involved in sexual reproduction for the formation of an offspring, each pair segregate independently from the other (just as a pair of homologous chromosomes separate) only one entering each gamete.

The segregation of one gene pair occurs independently of any other gene parent. In other words the alleles of two (or more) different genes get sorted into gametes independently of one another.

Dihybrid Cross Example in Pea Plants:

The parent genotypes in a dihybrid cross are both heterozygous for two genes. Let’s take a look at an example in pea plants;

Gene 1:

  • The first Gene is for seed colour and has two alleles, a dominant allele that results in a yellow seed colour (Y) and a recessive allele that results in a green pea colour (y).
  • The homozygous dominant (YY) and heterozygote genotypes (Yy) result in yellow seeds.
  • The homozygous recessive genotype (yy) results in green seeds.

Gene 2:

  • The second gene is for seed shape and has two alleles, a dominant allele that results in a round seed shape (R) and a recessive allele that results in a wrinkled seed shape (r).
  • The homozygous dominant (RR) and heterozygote genotypes (Rr) result in a round shape.
  • The homozygous recessive genotype (rr) results in a wrinkled shape.

This is illustrated in fig 1.5.1 below:

dihybrid crossing
Fig. 1.5.1.

 

You are viewing an excerpt of this Topic. Subscribe Now to get Full Access to ALL this Subject's Topics and Quizzes for this Term!

Click on the button "Subscribe Now" below for Full Access!

Subscribe Now

Note: If you have Already Subscribed and you are seeing this message, it means you are logged out. Please Log In using the Login Button Below to Carry on Studying!

Responses

Your email address will not be published. Required fields are marked *

error: Alert: Content selection is disabled!!