Hello.
I am trying to figure out how to solve polygenic Punnett squares. In order to get extra credit on a test, I have to learn how to use them. I've tried looking at images and tutorials, but I'm still confused.
if you google "polygenic punnett square practice", you will see "Punnett square practice and examples" at "bifidosoft"
it looks like a pretty good tutorial
Hello! I'd be happy to help you understand how to solve polygenic Punnett squares. Polygenic inheritance involves traits that are controlled by multiple genes, rather than just one gene. These traits often exhibit a wide range of phenotypes.
To solve polygenic Punnett squares, you need to follow a few steps:
1. Determine the number of genes involved: Polygenic traits involve two or more genes. For simplicity, let's assume we're working with a trait controlled by two genes.
2. Determine the possible alleles: For each gene, determine the possible alleles. Each gene can have multiple alleles, contributing to the variation in the trait. Let's assume each gene has two alleles: A and a for gene 1, and B and b for gene 2.
3. Cross the parental genotypes: Write out the genotypes of the parents. For example, if one parent is AABB and the other is aaBB, write them out vertically.
4. Distribute alleles: Distribute the alleles from each parent to create the gametes. Combine one allele from each gene to form a gamete. For example, from the AABB parent, you would have AB gametes, and from the aaBB parent, you would have aB gametes.
5. Create the Punnett square: Write out all possible combinations of alleles from the gametes. In our example, you would create a 4x4 Punnett square.
6. Determine the phenotypic expression: Assign phenotypes to the different genotypes. Remember that polygenic traits often exhibit a range of phenotypes, so assign a range of values to each genotype. For example, if AA represents the highest expression and aa represents the lowest expression, you might assign a scale from 1 to 5.
7. Calculate the probabilities: Calculate the probability of each phenotype by counting the number of squares that correspond to each phenotype and dividing by the total number of squares in the Punnett square.
Remember, this is a simplified explanation, and polygenic inheritance can be more complex. It's essential to understand Mendelian genetics and Punnett squares before tackling polygenic inheritance. Don't forget to consult your textbook or teacher's notes for more detailed information.
I hope this helps! Let me know if you have any further questions.