A scientist is studying the inheritance of two characteristics in plants: red flowers (RR and Rr), which are dominant to yellow flowers (rr), and green leaves (GG and Gg), which are dominant to yellow leaves (gg). She crosses a double heterozygous (RrGg) with a double recessive (rrgg), and expect to see a 1:1:1:1 ratio in the offspring. Instead, she sees these results: Genotype RrGg rrgg Rrgg rrGg Predicted outcome 500 500 500 500 Actual outcome 900 900 100 100 Which phenomenon would she hypothesize accounts for the pattern she sees? crossing-over respiration cytokinesis independent assortment

Question

Zain Allison

Biology

26 July, 16:18

A scientist is studying the inheritance of two characteristics in plants: red flowers (RR and Rr), which are dominant to yellow flowers (rr), and green leaves (GG and Gg), which are dominant to yellow leaves (gg). She crosses a double heterozygous (RrGg) with a double recessive (rrgg), and expect to see a 1:1:1:1 ratio in the offspring. Instead, she sees these results: Genotype RrGg rrgg Rrgg rrGg Predicted outcome 500 500 500 500 Actual outcome 900 900 100 100 Which phenomenon would she hypothesize accounts for the pattern she sees? crossing-over respiration cytokinesis independent assortment

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Answers (1)

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Jayvon Dudley · Answer 1

The correct option is B. Crossing - over

Explanation:

In biology, crossing over can be described as a phenomenon by which homologous chromosomes exchange segments during the process of meiosis.

The unexpected results came because the DNA segment between the homologous chromosomes was exchanged during meiosis. The alleles got shuffled by this process and hence showed the unexpected results.

Crossing over and independent assortment are phenomenon which occurs only during the process of meiosis. These phenomenons cannot be observed during mitosis.