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Author12 Posts

What method is used to determine paternity?

a. Northern Blot
b. PCR
c. Southern blot
d. RFLP analysis

Pls explain..



I think the philosphy is simple.The child has gained two chromosomes
  1. One from mother
  2. One from father

The repetitive DNAs of both chromosomes have peculiar Polymorphism.When we do RFLP of repetitive DNA
  1. One set of fragments always resembles with that of mother (makes sense)
  2. Other set of fragments should resembles with that of father (in case child is legitimate)

If the second set of fragments does not resemble with father then (Paternitiy doubtful)

Any other thought ????




"I concur"nod


southern blot


it is given as PCR in Kaplans notes


Actually PCR and Southern blot have different purposes

PCR = just like magnifying glass of a microscope.It simply increases the amount of DNA of interest

Southern Blot = detects the (makes it visible to naked eye) DNA by probes

while RFLP is the actual procedure done on DNA to detect the paternity or identity of any person (finger printing )

Best of luck


more than one answer is correct here
and it seems, as sridevibandaru mentioned, lately PCR analysis tops any other lab test


Yep, according to Kaplan, it is PCR amplification of microsatellite sequences


it is PCR amplification of microsatellite sequences


drpkaur wrote:
it is PCR amplification of microsatellite sequences

  • The frequencies of particular RFLP alleles may differ for different human subpopulations. This possibility engendered much discussion about the validity of using RFLP analysis for forensic purposes. RFLP's are molecular markers used in creating genetic maps of chromosomes. RFLP's have many other uses. In forensics, they are used to test whether a tissue sample left at a crime scene (blood, skin, sperm, etc.) could have come from the suspect. In plant and animal breeding, they can reveal which backcross progeny most resemble the desired parent. RFLP's are used to settle cases where biological parentage is at issue. They are used as starting points for chromosome walks. RFLP's are used in plant genetic analysis. Note that an RFLP is specified by a hybridization probe and a restriction enzyme."
  • [left]

    paternity Case
    Let's use RFLP technology to determine if Jack is the father of Jill's child named Payle.

    In this scenario, DNA was extracted from white blood cells from all three individuals and subjected to RFLP analysis. The results are shown below:

    In this case, it appears that Jack could be the father, since Payle inherited the 12.4 kb fragment from Jill and the 4.3 fragment from Jack. However, it is possible that another man with similar RFLP pattern could be as well.To be certain, several more RFLP loci would be tested. It would be highly unlikely that two men (other than identical twins) would share multiple RFLP patterns and so paternity could be confirmed.

    In a different scenario, DNA was extracted from white blood cells from all three individuals and subjected to RFLP analysis. The results are shown below:

    This time, it can be determined that Jack is NOT the father of Payle since Payle has a band of about 6 kb and Jack does not. Therefore, it is very probable that Payle's father is not Jack, though it is possible that Payle carries a new mutation at this locus and a different sized band was produced. What could you do as an investigator to be more certain that Jack was not the father of Payle?
    Best of luck


  •   #12

    so D is the ans. is it right goodyear?

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