Environmental effects on phenotype Transitional Reasoning Download PDF

Questions

1. 1.

   A biologist investigating gene expression shaved a patch of fur on the backs of genetically identical Himalayan rabbits that are homozygous for the coat color allele ch. Group 1 had an ice pack applied continuously to the shaved patch at an ambient room temperature of 22°C during hair regrowth, while Group 2 was maintained at the same ambient temperature without an ice pack. Group 1 grew black fur in the chilled area, whereas Group 2 grew white fur across the entire shaved area. Which conclusion is best supported by these experimental results?

   • A) Environmental factors such as cold temperatures induce novel genetic mutations that permanently alter the rabbits' nuclear DNA sequence.
   • B) An organism's genotype is directly determined by external thermal fluctuations during tissue regeneration rather than by inheritance.
   • C) Environmental conditions can influence how an identical genotype is expressed as an observable physical phenotype.
   • D) The observed coat color differences demonstrate that phenotypic variation arises entirely independently of any genetic control.