Paleogene- Radiation of mammals, birds, snakes, angiosperms, pollinating insects

#Id: 2533

#Unit 13. Methods in Biology

The ‘Wallace rule’ (Lay Thein & Wallace 1986) is used to determine the appropriate stringency wash temperature: 

#Id: 2534

#Unit 13. Methods in Biology

Probe length for PCR – the longer the oligonucleotide, the less chance there is of it binding to sequences other than the desired target sequence under conditions of high stringency.

#Id: 2535

#Unit 13. Methods in Biology

Oligonucleotide composition for PCR– the GC content will influence the stability of the resultant hybrid and hence the determination of the appropriate stringency washing conditions

. 

#Id: 2536

#Unit 13. Methods in Biology

At the second cycle of PCR, primers will anneal to the 'long product' at sites where sequences complementary· to them are located, which will be much before the actual 3'-end of the long product.

#Id: 2537

#Unit 13. Methods in Biology

Extension step in the second cycle will produce a product that will be much shorter than the 'long product'; this is the 'correct' PCR product and represents the target sequence

#Id: 2538

#Unit 13. Methods in Biology

The original template sequence will also be copied during the second and all subsequent cycles to generate the 'long product'. Therefore, the long product continues to increase linearly, while the 'correct PCR' product will multiply exponentially.