In a study of Drosophila, two normally active genes, w⁺ (wild-type allele of the white-eye gene) and hsp26 (a heat-shock gene), were introduced (using a plasmid vector) into euchromatic and heterochromatic chromosomal regions, and the relative activity of each gene was assessed [Sun et al. (2002)]. An approximation of the resulting data is shown in the following table. Which characteristic or characteristics of heterochromatin are supported by the experimental data? Gene Activity (relative percentage) _ Euchromatin Heterochromatin hsp26 100% 31% w⁺ 100% 8%

Video transcript

Hey everyone. Let's take a look at this question together. Which of the falling options can be used to define a phenotype that is stable E inherited and is caused by changes in chroma tin but not D. N. A. Sequence. So let's take a look at the following options to figure out which one best defines a phenotype that is stable we inherited and is caused by changes in chrome a tin but not in D. N. A. Sequence. While starting off with answer choice A. We can see mutation which we know that a mutation is caused by changes in D. N. A. Sequence. So a change in the D. N. A. Sequence would make answer choice a incorrect so it is not a mutation. Answer choice B says an autism trait which we do know autism traits are passed down from parent to child through that autism a dominant inheritance. However a condition past down can be a mutation which we do know that mutations are caused by changes in that D. N. A. Sequence and so answer choice B. Is also incorrect answer choice E says sex linked trait which we know that a sex linked trait refers to sex specific inheritance such as excellent recessive, excellent, dominant and wide linked in humans. But those genetic changes in those sex linked traits are also examples of changes in D. N. A sequences. And so it cannot be a sex linked trait which means by process of elimination. The correct answer has to be answer choice D. Epigenetic trait which we also know is the correct answer. Because those epigenetic changes can be reversed because they do not alter the N. A. Sequences, which the question is asking us about, A phenotype that is stable inherited caused by changes in chrome button but not D. N. A sequence, which is an epigenetic trait. Since those epigenetic traits alter how your body interprets the D. N. A. Sequence instead of changing that D. N. A. Sequence and that is why answer choice D. Is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.