Multiple Choice
Which method is most commonly used to separate genomic DNA fragments by size?
22
views
18. Molecular Genetic Tools
Methods for Analyzing DNA
Multiple Choice
In forensic DNA analysis, which part of a human hair is most likely to contain sufficient nuclear DNA for STR profiling?
A
The hair follicle (root) with attached cells (follicular tag)
B
The hair cuticle only
C
The hair cortex only
D
The hair shaft (keratinized portion) without the root
Verified step by step guidance1
Understand the structure of a human hair, which consists of three main parts: the cuticle (outer layer), the cortex (middle layer), and the hair follicle or root (the base part embedded in the skin).
Recall that nuclear DNA is primarily found in living cells, so the part of the hair containing living cells or cellular material is most likely to have sufficient nuclear DNA.
Recognize that the hair shaft, including the cuticle and cortex, is mostly composed of keratinized (dead) cells, which contain little to no nuclear DNA.
Identify that the hair follicle (root) contains the follicular tag, which is a small piece of tissue attached to the root and contains living cells with intact nuclear DNA.
Conclude that for STR (Short Tandem Repeat) profiling, which requires nuclear DNA, the hair follicle with the follicular tag is the best source of DNA in a hair sample.
Related Videos
Related Practice
