genetics question

Question

Hello, I was wondering in genetics I am in need of some help with understanding the short cut of doing monohybrid and dihybrid crosses. Like I am confused with the question how many different gametes can this parent make for both monohybrid crosses and dihybrid crosses. I know that at the end of meiosis the result is 4.

Answer 1

I think I understand what you're asking!

Each parent contributes different types of gametes. While yes, in meiosis, a certain number of gametes are produced, based on your question, I think you're looking at Punnett squares and therefore you're looking for the types of gametes each parent can produce.

Let's picture a monohybrid cross, for one allele, where H is the dominant allele and h is the recessive allele. With this scenario, each parent can only contribute one allele to each gamete. The male parent can contribute an H gamete OR an h gamete, and a female parent can contribute an H gamete or an h gamete. Therefore, each parent can make two different gametes for a monohybrid cross.

For a dihybrid cross, there are two alleles, and we will use the letters A and a (for the dominant and recessive first allele) and B and b (for the dominant and recessive second allele) (for example, one offspring may have the alleles AABb, another AaBB, etc.). Here, each parent can contribute four different, unique gametes. The male parent can contribute an AB, Ab, aB, or ab gamete, and the female parent can contribute an AB, Ab, aB, or ab gamete. Therefore, each parent can make four different gametes for a dihybrid cross.