Question

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: Which phenomenon would she hypothesize accounts for the pattern she sees?crossing-overindependent assortmentcytokinesisrespiration

Answer 1

It wouldn't be respiration, because it has no direct relation to procreation. It wouldn't be independent assortment also, because this is the phenomenon that would explain the expected result. It also wouldn't be cytokinesis because this phenomenon is related to cell division, in which the combinations are already set. So, it is crossing-over, because this phenomenon occurs when ther is a switch between homologous chromatids occured during meiosis, which means that the chromosomes are so close to each other that they can trade parts of itselfs with other chromosomes, unexpectedly providing a different outcome than the one that was expected. So, the answer is crossing-over.