BSFS Forensic Biology and DNA Analysis 2

Question 1

A mixed DNA profile occurs when a forensic sample contains genetic material from:

Accepted Answer

Two or more contributors

Answer

Mixed profiles contain alleles at one or more loci from multiple individuals, which complicates statistical interpretation and contributor deduction.

Question 2

Touch DNA refers to DNA recovered from:

Accepted Answer

Skin cells deposited when a person handles or touches an object

Answer

When a person touches a surface, they deposit epithelial (skin) cells containing nuclear DNA, which can be collected and profiled even without visible biological fluid.

Question 3

Y-STR analysis is specifically used in sexual assault cases because it can:

Accepted Answer

Distinguish the male contributor's profile from a predominantly female victim sample

Answer

Y-STRs target the male-specific Y chromosome, allowing the male contributor's profile to be recovered even from mixtures dominated by female DNA.

Question 4

The differential extraction technique is used in sexual assault evidence to:

Accepted Answer

Separately isolate sperm cell DNA from non-sperm (epithelial) cell DNA in a mixed sample

Answer

Differential extraction exploits the different cell wall structure of sperm cells to separate them from epithelial cells before DNA extraction, reducing mixture complexity.

Question 5

In STR analysis, 'allelic dropout' refers to:

Accepted Answer

Failure to detect one or both alleles at a locus due to low or degraded DNA

Answer

Allelic dropout occurs when a true allele is not amplified or detected, typically due to degraded template DNA or inhibitors, potentially causing a false exclusion.

BSFS - Bachelor of Science in Forensic Science Practice Test

BSFS - Bachelor of Science in Forensic Science Practice Test

BSFS Forensic Biology and DNA Analysis 2