Lineage Markers
- Created by: AAntonianannetti
- Created on: 12-05-19 12:07
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- Lineage Markers
- Y- Chromosomes
- Passed from father to son
- Is only found in males
- Helpful in crimes that involve males
- Sex Chromosome
- Non-recombining
- Is only found in males
- The second smallest chromosome with a length of approximately 60 millions nucleotides.
- Y chromosome testing is important
- Forensic evidence examination
- Paternity tests
- Migration patterns
- Y-STRs are found on the Y-Chromosome
- When a profile is found to match, the significance needs to be assessed.
- Done through the frequencies of Y-STR haploid types in the population
- Counting method - use of databases
- Done through the frequencies of Y-STR haploid types in the population
- 400 Y-STR loci have been mapped along the chromosome, but only a small set of core loci have been analysed.
- When a profile is found to match, the significance needs to be assessed.
- Y chromosome testing is important
- Random mutations are the only mechanisms for variations
- Need to be considered to prevent false exclusions
- Passed from father to son
- mtDNA
- Passed from mother to child
- An organelle in the cytoplasm of eukaryotic cell.
- Contains its own genome from the mum
- Circular
- Smaller than a nuclear genome
- During conception, only the sperms nucleus enters the egg and joins directly with the eggs nucleus
- The sperm does not contribute other celluar components
- Contains its own genome from the mum
- High copy number
- Mitochondria has loads of copies of DNA of the mitochondrial genome
- Nuclear DNA only has 2 copies of DNA
- High probability of obtaining a DNA typing result from mtDNA
- Mitochondria has loads of copies of DNA of the mitochondrial genome
- An organelle in the cytoplasm of eukaryotic cell.
- Hyper Variable Regions
- 2 main regions that are focused on in forensics
- HV2
- 2 main regions that are focused on in forensics
- Use of mtDNA
- maternal inheritance is not unique to the individual and therefore when there are no direct relatives for a reference sample other relatives can be used
- Historical cases
- If there is more than one difference in samples, then this is inconclusive.
- This is because there is only on mutation in bases,
- Little discrimination between the mtDNA sequences of the same maternal lineage
- This is because there is only on mutation in bases,
- maternal inheritance is not unique to the individual and therefore when there are no direct relatives for a reference sample other relatives can be used
- Methods of analysis
- Determination of haplotype frequency
- Comparison with a reference sample
- Sanger sequence
- Passed from mother to child
- Transferred directly from generation to generation without changing.
- Exceptions with mutation
- Do not follow menedlian inheritance
- Do not recombine
- Genetic information is referred to as a haplotype rather than a genotype because there is only a single allele per individual.
- Y- Chromosomes
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