Genetics: ? Restriction fragment length polymorphism (RFLP) can be used to detec
ID: 175757 • Letter: G
Question
Genetics: ?
Restriction fragment length polymorphism (RFLP) can be used to detect different types of diseases. One such disease or ailment is the herpes virus, which comes in many forms and can cause a multitude of issues from cold sores to meningitis. Four such herpes viruses include herpes simplex virus type 1 and 2 (HSV-1/-2), Epstein-Barr virus (EBV) and cytomegalovirus (CMV). RFLP was used to differentiate these four different herpes viruses, in which restriction enzyme digestions with BamHI and BstUI were used to detect presence or absence of the disease. Below are the results from this RFLP, included is a description of the contents of each lane.
What are the results telling us? How could I use this technique to test a patient for herpes virus?
CMV HSV2 EBV HSV1 1000bp 750bp 500bp 250bn 100bp Figure 1. Detection of CMV, EBV, HSV-1 and HSV-2 by restriction enzyme digest. Lane M: molecular weight digestion with BamHTLane 3: amplified fragments without restriction enzyme analysisExplanation / Answer
The interpretation for these RFLP maps can be deciphered as below:
CMV: The restriction digestion by BstUI yields a differential molecular weight range whereas that with BamHI does not digest the genome of CMV. This suggests that CMV genome is devoid of restriction site for BamHI. A positive control of non-digested amplified band supports this data.
EBV: The restriction digestion with BstUI and BamHI yield similar type of genotype banding whereas intact band is found in undigested genome. This suggests that both restriction sites are present very close in this virus.
HSV1: The presence of a differentially digested band pattern by BstUI gives an indication that these restriction sites are present in this virus whereas similarity in band pattern of BamHI digested and undigested sample suggests that BamHI sites are absent from HSV1.
HSV1: The presence of differential BstUI and BamHI sites with clear difference from undigested sample suggests that both restriction sites are present in this virus.
Collectively, this set of information suggests following:
1. The average size of genome of these viruses is nearly similar
2. All viruses except EBV carry a restriction site for BstUI
3. HSV and CMV carry more sequence similarity as compared to others as they have similar BstUI digestion patterns.
4. EVB and HSV2 carry more sequence similarity as compared to others because they have similar BamHI digestion patterns.
These data suggest that differential/combinatorial digestion of patient's genome with BstUI and BamHI can help in qualitative assessement of presence/absence of disease by analysis of relative changes in banding pattern. Thus, a person with restriction digestion with both enzyme can be deciphered to have the nature of infection (by virus) by comparing its digestion pattern with others.
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