DNA amplification- size separation of STR markers

How does gel based analysis work

• It van be simple PCR of target region

• Can be PCR and restriction digest

• Agarose gel at 2-3% stained with ethidium bromide

• Sep

What does STRs stand for

Short tandem repeats

What are the different repeat units that STr can exist as

Di

Ti

Tetra

Penta

Hexa 

Strcuture and function of STR’s

• They are co-dominant 

• Inherited in a mendelian fashion- means you inherit one from both parent 

• There will be 2 copies of each locus for each chromsome pair 

STRR structure and function

Alles you inherit from your parents may be the same size- homozygote

When visualised it shows one peach- one is hiding behind the other 

Why does repeat unit structure have variation

Occurs due to mutations during cell division

This can result in the loss or gain of repeat units

What are the different categories of mutations within the STR repeat unit

Simple repeats

Simple repeat with non-consensus alleles

Compund repeats

Complex repeats

What are simple repeats

Contain units of identical length and sequence

What are cmpound repeats

They comprise two or more adjacent simple repeats

What are complex repeats 

contain several repeat blocks of variable unit length