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Correct Answer:
the gene for coat color is near the locus that determines ear placement.
in genetics, the phenomenon where two traits often appear together more frequently than expected by chance is referred to as genetic linkage. this typically occurs when genes for different traits are located close to each other on the same chromosome. the proximity of these genes reduces the likelihood that they will be separated during the process of genetic recombination that occurs during meiosis, the form of cell division that produces gametes (sperm or eggs).
in the scenario described, the researcher observes that mice with white pelts tend to have ears that are wider apart compared to their brown-coated siblings. this recurring pattern suggests that the genes influencing coat color and ear placement might be linked. genetic linkage would mean that the gene responsible for coat color and the gene controlling the width between ears are located near each other on the same chromosome. therefore, they are likely inherited together more often than not.
during meiosis, chromosomes are duplicated and then divided into gametes. each gamete receives a mix of parental chromosomes, but genes that are close together on the same chromosome are less likely to be separated by recombination, a process where segments of dna are shuffled. thus, linked genes tend to be passed on as a unit, which could explain why certain traits, like white coat color and wider ear placement in this case, appear together frequently.
the correct answer, "the gene for coat color is near the locus that determines ear placement," is supported by this understanding of genetic linkage. other options such as mitochondrial inheritance or dominance/recessiveness patterns do not specifically address the observed correlation between these two particular traits. moreover, mitochondrial dna is inherited maternally and does not undergo recombination, which is inconsistent with the pattern described. meanwhile, dominance and recessiveness affect the expression of traits rather than their inheritance together.
understanding the genetic basis of traits and their linkage is crucial for fields such as genetics, breeding, and evolutionary biology. it helps in predicting the inheritance patterns of certain traits, which can be particularly useful in selective breeding programs or in studying the genetic architecture of complex traits in natural populations.
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