Module 6 : Genetic fingerprinting (DNA profiling) Flashcards
DNA profiling is …
a technique used to identify unique DNA patterns in individuals , to help identify individuals in forensics or family relationships
What are variable number tandem repeats?
unique , non coding , repetitive DNA segments
What are the 6 key features of VNTR’s?
1)they are present across the genomes of most eukaryotes
2)they aren’t involved in protein coding
3)they vary in sequence and length between individuals
4)their length and location are heritable
5)the chance of individuals who aren’t identical twins sharing identical VNTR patterns is very low
6)a high similarity in VNTR patterns indicates 2 individuals are very closely related
What are the 5 processes involved in creating a DNA profile ?
(DDFHD)
1) DNA extraction
2) DNA digestion
3) Fragment separation
4)Hybridisation
5)Development
Make 1 point about DNA extraction and 1 point about DNA digestion
DNA extraction-DNA extracted from tissue sample and amplified using PCR
DNA digestion-restriction enzymes are used to cut the DNA fragments at points near the VNTR sequences
Make 2 points about fragment separation and 1 point about hybridisation
fragment separation-gel electrophoresis separates the fragments by size , and they are denatured to produce single strands
hybridisation-specific radioactive or fluorescent probes bind to complementary VNTR sequences
Make 1 point about development of a DNA profile
the positions of the fluorescent/radioactive probes are revealed which creates a barcode like pattern of DNA bands unique to an individual
Give 3 key uses of DNA profiling technology
-establishing paternity by matching bands on a childs profile with those of potential parents to assess similarities in VNTR sequences
-identifying suspects from crime scene DNA
-supporting criminal convictions with match probability calculations
Give 3 other key uses of DNA profiling technology
-identifying risk of genetic disorders and predicting their onset and severity
-selecting desirable traits in animals and plants for selective breeding while preventing severe inbreeding
-evaluating genetic diversity by comparing variety of DNA profiles in a population
Give 3 limitations of DNA profiling
-environmental contamination may compromise results
-close genetic relatives could have similar profiles
-DNA profiling does not prove guilt or causation as assumptions about genetic variation in populations underpin probability calculations (other evidence must be considered)
