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Genomic Variation quiz

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  • What is a single nucleotide polymorphism (SNP)?
    A SNP is a single nucleotide change in the DNA sequence, such as an A to a C or a G to a T.
  • How frequent are SNPs in the human genome?
    SNPs occur about once every 1,000 bases, totaling approximately 18 million in the human genome.
  • Where are most SNPs found in the human genome?
    Most SNPs are found in non-coding regions that do not affect protein function.
  • Why are SNPs important for scientists even if they do not affect proteins?
    SNPs are useful for genetic identification and studying evolutionary relationships between individuals.
  • Name three techniques used to identify SNPs.
    SNPs can be identified using Southern blotting, PCR, and DNA microarrays.
  • How do restriction enzymes help identify SNPs?
    Restriction enzymes cut DNA at specific sequences, and SNPs can alter these sites, resulting in different DNA fragment lengths.
  • What is a deletion/insertion polymorphism (indel)?
    An indel is a small deletion or insertion of genetic material, ranging from 1 to 517 base pairs.
  • How common are indels in the human genome?
    There are nearly 300,000 indels in the human genome, occurring about once every 10,000 bases.
  • What are simple sequence repeats (SSRs) and how do they arise?
    SSRs are short sequences of 1-3 bases repeated 15 to 100 times, often arising from DNA replication errors.
  • Which disease is associated with a simple sequence repeat expansion?
    Huntington's disease is associated with an expanded CAG simple sequence repeat.
  • How frequent are CA simple sequence repeats in mammalian genomes?
    CA repeats are found about once every 30,000 base pairs in mammalian genomes.
  • What are mini satellites and how are they used in forensics?
    Mini satellites are repeated DNA sequences 500 bp to 20 kb long, used in DNA fingerprinting for forensic identification.
  • What is a DNA fingerprint and how is it generated?
    A DNA fingerprint is a unique pattern of mini satellite repeats in an individual's genome, visualized by analyzing the lengths and frequencies of these repeats.
  • What are large scale deletions and what is an example?
    Large scale deletions are the loss of large DNA regions, with copy number variants being a common example.
  • How can DNA fingerprinting be used to match a suspect to a crime scene?
    By comparing the pattern of mini satellite repeats in DNA from the crime scene to suspects, the individual with the matching pattern can be identified.