If the F1 generation allows for self-pollination, what will be the genotypic ratio of the offspring?

Assessment: JAMB UTME - Biology - 2024 Subject: Biology

Question 1 Report

If the F1 generation allows for self-pollination, what will be the genotypic ratio of the offspring?
Answer Details

To determine the genotypic ratio of the offspring when the F1 generation allows for self-pollination, first understand the process of Mendelian genetics. In a typical monohybrid cross, let's assume two homozygous parents, one dominant (AA) and one recessive (aa). When these two are crossed, the F1 generation will all have the genotype Aa, which is heterozygous.


If we allow the F1 generation (Aa) to self-pollinate, crossing Aa with Aa, the potential genotypes of the offspring can be determined using a Punnett square:


A a
A AA Aa
a Aa aa


From this Punnett square, you can see the possible combinations:

  • 1 AA
  • 2 Aa
  • 1 aa

Thus, the genotypic ratio of the offspring is 1 : 2 : 1, which represents one homozygous dominant (AA), two heterozygous (Aa), and one homozygous recessive (aa).

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