DNA profiling
No description yet. This curated deck is ready for daily study.
Card preview (20)
Is everyone’s DNA the same?
No, except for identical twins
What is DNA profiling used for?
Using DNA to distinguish between and/or identify individuals
Who developed DNA fingerprinting and when?
Professor Alec Jeffreys in 1984
Why is DNA profiling so good?
The chances of two people having exactly the same DNA profile is 30,000 million to 1 (except for identical twins) DNA is robust and stable under most environmental conditions DNA can be isolated from a wide range of biological samples likely present at a crime scene
Advantages of DNA fingerprinting?
• The source of DNA doesn’t matter – it is the same in all sources (blood, semen, sputum, skin etc) • Even with very small samples (a blood spot, single hair follicle, lip-prints on a glass, physical fingerprints, saliva/skin on a cigarette butt etc) • Methods are fast and relatively cheap • Data are complied in databases, and are easily searched
What cells can be used for DNA fingerprinting?
• Blood (White blood cells) • Semen (Sperm cells) • Hair with roots (Hair follicle cells) • Skin, dandruff (Skin cells) • Sweat stains (Skin cells sloughed off) • Vaginal fluids (Mucosal surfaces) • Nasal secretions (Mucosal surfaces) • Urine (Mucosal surfaces) • Faeces (Digestive system cells)
What are the uses of DNA fingerprinting?
Identification of remains Murder/rape cases Paternity cases Exoneration!
Does every cell in your body contain the same set of DNA?
Yes
What percentage of our DNA do we share with everyone else?
99.9%
The remaining 0.1% of our 3 billion nucleotides that we don’t share with others, is this a significant and detectable level of difference?
Yes, this is 1 out of every 1000 nucleotides
Where do most of the DNA variations take place?
Non-coding junk DNA
What happens when mutations occur within the non-coding DNA in an organism?
Nothing, the organism can tolerate and accumulate these mutations with no affect to the organism.
What does RFLPs stand for?
Restriction Fragment Length Polymorphisms
What are STRs?
Short Tandem Repeats
Is this an example of an STR? ACTG-GCC-GCC-GCC-GCC-ATCGACC
Yes this is a 4 tandem repeat
What does SNP mean?
Single nucleotide polymorphism
What percentage of DNA is tandemly repetitive?
10-15%
What are STRs also known as?
Satellite DNA
Variations in satellite length are used for DNA fingerprinting, but what is the most useful type?
Microsatellite DNA Only a few base pairs that are repeated 10-100 times
On a gel there are two bands, where are they likely to have come from?
One from each parent