While Working on Drosophila, You Find a New Mutant Strain

question 67

Multiple Choice

While working on Drosophila, you find a new mutant strain with an abnormal histone H3 gene. This novel histone mutant is predicted to cause the nucleosomes to bind an extra 15 bp of DNA compared to wild type. If you digest isolated chromatin with a nuclease to release the core nucleosomes, what size DNA fragments would you expect from wild-type and mutant flies?

• A) Approximately 50 bp is known to bind to the normal core nucleosome, so the additional 15 bp binding to H3 would give a rise to ~65 bp.
• B) Approximately 100 bp is known to bind to the normal core nucleosome, so the additional 15 bp binding to H3 would give a rise to ~115 bp.
• C) Approximately 125 bp is known to bind to the normal core nucleosome, so the additional 15 bp binding to H3 would give a rise to ~140 bp.
• D) Approximately 145 bp is known to bind to the normal core nucleosome, so the additional 15 bp binding to H3 would give a rise to ~160 bp.
• E) The size of the DNA fragments cannot be determined.

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Definitions:

Parietal Lobe

One of the four major lobes of the cerebral cortex, playing a key role in processing sensory information such as touch, temperature, and pain.

Thin Stripes

Thin stripes are regions within the visual cortex that specialize in processing color information.

Thick Stripes

Thick stripes refer to bands of neurons in the visual cortex that are involved in processing motion detected by the visual system.

Area V2

A part of the visual cortex that processes visual information, playing a key role in the perception of visual depth, texture, and color.