1 / 13

DNA Profiling

DNA Profiling. DNA Profiling. There are two methods used to carry out DNA profiling DNA profiling using a probe DNA profiling using PCR Knowledge of this is not required It is the more common method now days. DNA profiling using a probe.

yetta-chan
Download Presentation

DNA Profiling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DNA Profiling

  2. DNA Profiling • There are two methods used to carry out DNA profiling • DNA profiling using a probe • DNA profiling using PCR • Knowledge of this is not required • It is the more common method now days

  3. DNA profiling using a probe • This procedure relies on Minisatellites or Variable Number Tandem Repeats (VNTR) • VNTR are sequences of DNA 10 – 100bp long that repeat • The number of repeats is inherited resulting in sections of DNA of different length (can be between 0.5kbp – 40kbp)

  4. DNA profiling using probes- procedure • Isolate DNA • DNA is isolated from sample using organic solvent which dissolves proteins leaving DNA • If DNA quantity is insufficient PCR will be performed (note this is different to the method of DNA profiling using PCR)

  5. DNA profiling using probes – procedure cont… • Restriction enzyme digestion • Restriction enzyme which doesn’t cut in the minisatellite region is chosen • Creates DNA fragment of different sizes

  6. DNA profiling using probes – procedure cont… • Gel electrophoresis • Used to separate the different sized fragments

  7. DNA profiling using probes – procedure cont… • Blotting DNA onto a filter (Southern Blotting) • DNA is denatured using, for example, a strong alkali – this creates single stranded DNA • Single stranded DNA (still in the electrophoresis pattern) is transferred to a filter

  8. DNA profiling using probes – procedure cont…

  9. DNA profiling using probes – procedure cont… • Hybridisation with probe • Labelled (either radioactively or fluorescent) probe which binds to a specific base sequence in the target fragments. • Multi-locus probes bind at more than one site. Used where certainty needs to be very high. • Single locus probes – bind to 1 sequence (giving 2 bands for each sequence)

  10. DNA profiling using probes – procedure cont… • Create autoradiograph • Creates permanent record of the filter (usually using x-ray film) • If using multi-locus, the filter is then washed and another probe is used to add to the autoradiograph

  11. Interpreting Autoradiograph – to establish paternity • After using a single locus probe 2 bands are present • As the VTNR forming the ‘band’ is inherited, 1 band is from maternal DNA, the other from paternal DNA. • Therefore, a person that has the same band as another person is potentially related. • A child’s bands should match one of the mothers and one of the fathers. • If this is not the case…….

  12. Learning Activities • Monograph pg 84 – 90 • DART pg 87 – 88 • Scholar 9.4 • DNA profiling using Probes worksheet • DNA profiling using PCR worksheet (extension) • Assignment questions 2001 Q11, 2002 Section C 1B, 2003 Q12, 2006 Q12

More Related