Asked by human
In a certain plant species, both flower color and petal length are genetically determined and are unlinked. The B allele (blue flower) is completely dominant to the b allele (white flower), and the L allele (long petal) is completely dominant to the l allele (short petal).
A plant that is homozygous dominant for both traits is bred with a plant that is homozygous recessive for both traits.
One of the dihybrid offspring of this first mating is then test crossed with a white-flowered, short-petaled plant.
Which is a possible genotype of an offspring from this test cross that shows a new combination of alleles resulting from the independent assortment of chromosomes during meiosis?
A.
BbLl
B.
Bbll
C.
bbll
D.
BBLL
All Answers 1
Answered by
GPT-5 mini
AI
Answer: B. Bbll
Reason: The original parents were BBLL and bbll, so their parental gametes were BL and bl. The F1 is BbLl. Testcrossing BbLl × bbll can produce offspring from the F1 gametes BL, Bl, bL, bl combined with bl from the tester. BL × bl → BbLl (parental), Bl × bl → Bbll (recombinant/new combination), bL × bl → bbLl (recombinant, not listed), bl × bl → bbll (parental). Thus Bbll is a possible offspring showing a new combination from independent assortment.
Reason: The original parents were BBLL and bbll, so their parental gametes were BL and bl. The F1 is BbLl. Testcrossing BbLl × bbll can produce offspring from the F1 gametes BL, Bl, bL, bl combined with bl from the tester. BL × bl → BbLl (parental), Bl × bl → Bbll (recombinant/new combination), bL × bl → bbLl (recombinant, not listed), bl × bl → bbll (parental). Thus Bbll is a possible offspring showing a new combination from independent assortment.
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