Simple Genetic Cross Example Using Punnett Squares #punnettsquare #genetics

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Learn more about Genotypes and Phenotypes here:

Let’s solve a simple genetic cross using a Punnett square.

In rabbits, coat color is determined by a single gene with two alleles: uppercase B (brown coat) and lowercase b (white coat). A homozygous dominant brown-coated rabbit (BB) is crossed with a homozygous recessive white-coated rabbit (bb). Determine the possible genotypes and phenotypes of their offspring.

To start, let’s set up our Punnett square. We will put the brown-coated rabbit alleles across the top. Both uppercase B.

And the white-coated rabbit on the side. Both lowercase b.

Now we match up the alleles in their corresponding squares. In this case, every square gets one big B and one little b.

So these are the possible outcomes, and the question asked for the possible genotypes and phenotypes.

Genotypes are the alleles, which are 100% heterozygous, big B and little b.

The phenotype refers to the expression of the genes. Given that there is only one genotype, we only have one phenotype, brown-coated rabbits.

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Excellent explanation. I would say however (and this is just the way I was taught) that if you have 2 of the same letters, like BB and bb, I would only cross B with b in the Punnet square. It makes the ratios easier to find, and also generally simplifies the whole process.
I love this explanation tho! Keep on making good content! 👍

victorcoste-qpwm

Never learnt this before, now watching an hour before my exam 😅 wish me luck ig

Joseph-fppm

You explained it better than the book lol. Thank you!

Santino-bo

Tysm! It helped me for my exam tomorrow!

Notmarianaroblox

God Almighty continue blessings me with a listening heart to complete my studies 🙏🏽💯

AgookMatuong-khhxtuf

Tip you can also change the BB and bb in the punnett square like BB in the left side and bb at the top side. Both had the same possibilities.

MatsuroFATE