How do you find a primer to do PCR for unknown DNA sample from crime scene?

tazz233

Just to clarify. Primers for Short tandem repeates (STR's) are designed to bind upstream and downstream of the repeat array. This is so the binding site is kept constant in all individuals, yet the PCR product length will be different for different people (depending on the length of the repeat). Screening a number of these STR's (or other repeat elements) creates a individual profile similar in complexity to a standard DNA profile created by restriction digests of the whole chromosome.

Hope that clears things up a bit. :beer:

pavlovs_dog

tazz233 wrote:

Just to clarify. Primers for Short tandem repeates (STR's) are designed to bind upstream and downstream of the repeat array. This is so the binding site is kept constant in all individuals, yet the PCR product length will be different for different people (depending on the length of the repeat). Screening a number of these STR's (or other repeat elements) creates a individual profile similar in complexity to a standard DNA profile created by restriction digests of the whole chromosome.

Hope that clears things up a bit. :beer:

clear as mud but then im not a scientist

Basil_Fawlty

tazz233 wrote:

Just to clarify. Primers for Short tandem repeates (STR's) are designed to bind upstream and downstream of the repeat array. This is so the binding site is kept constant in all individuals, yet the PCR product length will be different for different people (depending on the length of the repeat). Screening a number of these STR's (or other repeat elements) creates a individual profile similar in complexity to a standard DNA profile created by restriction digests of the whole chromosome.

Hope that clears things up a bit. :beer:

Thanks Tazz :beer: It is clear (as crystal, not mud ) but strange how you addressed that because I was just thinking this morning, surely only a short (ish) strand will be sequenced/amplified by PCR surely not enough for a match. I was going to look it up but you've saved me the trouble. :beer:

Ever considered becoming a psychic?! Here's me taking my own thread off-topic