Two experimental varieties of strawberry are produced by...

Question

Two experimental varieties of strawberry are produced by crossing a hexaploid line that contains 48 chromosomes and a tetraploid line that contains 32 chromosomes. Experimental variety 1 contains 40 chromosomes, and experimental variety 2 contains 56 chromosomes.

How many chromosomes from the tetraploid lines are contributed to experimental variety 1? To experimental variety 2?

Accepted Answer

Hi, everyone. Let's take a look at this practice problem together. A variety of potato is produced with 60 chromosomes by crossing a tetraploid line with 48 chromosomes with a hex aid line that contains 72 chromosomes, determine the number of chromosomes contributed by the Hex Aloed line. The answer options are a 12 b 24 C D 48. So to solve this and help us work through the problem, let's use a picture and I am putting that up on the screen right now. So in this picture, all the cells are represented by circles and there's five cells total on the left is the tetraploid line. The tetraploid cell produces a gammy which is depicted below it. Now, on the right is the Hex Aloed line and the hex aloed cell produces a gammy, which is depicted below it as well. The two games, one from the tetraploid and one from the Hexapod combine and they produce the potato variety that has the 60 chromosomes. So recall in genetics that the letter N represents the number of chromosomes in a single set and tetra means four. So a tetraploid cell would have four sets of chromosomes. And in the tetraploid cell, we will write four N equals 8, 48 4 sets of chromosomes with the total chromosomes total. Now, the gammy produced from this tetraploid cell would contain half the amount of chromosomes. And so inside the gammy cell, for the tetraploid line, I will write two N equals 24. Now let's talk about the Hexapod line. Hexham means six. So this is a cell with six sets of chromosomes. So inside the hex aid cell, we will write six N equals 72. And the gammy it produces, would contain half the amount of chromosomes. So three N equals 36. That means that when these gametes fertilize, it will combine to make the 60 chromosomes. So 24 from the tetraploid and 36 from the hex alo. So the correct answer is option C 36. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.

Key Concepts

Polyploidy

Chromosome Contribution in Hybridization

Chromosome Counting in Offspring

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