Varibility in genome

Question 1

How can variation be detected at different level

Answer 1

1. Visible phenotypes
2. Chromosomal rearrangements (able to identify cross over)
3. Immunological markers (ABO blood system)
4. DNA markers • Single Nucleotide Polymorphisms (SNPs) • Copy Number Variations (CNVs)

Question 2

Type of DNA Markers

Answer 2

-SNP: A nucleotide pair difference at a given location in the genome of two or more naturally occurring individuals that Can be identified by DNA sequencing
Copy Number Variations (CNVs)
• Copy number variation for 2-5 base pair sequences
• Found at many loci throughout the genome
• Many alleles per locus defined by different copy numbers
• Usually outside coding regions
• they are Markers – identifying individuals (forensics – crime or disasters), paternity, population structure and movement via gel electrophoresis

Question 3

DNA markers can be

Answer 3

• Nuclear
•Autosomes
•Y Chromosome (Copy Number Variation is scored at multiple loci to produce a haplotype)
• Mitochondrial DNA (DNA sequences of the hypervariable control region or whole-genome used to generate markers)
-.Y chromosomes and mitochondrial DNA are particularly useful for tracing human history

Question 4

Mutations – How do they occur?

Answer 4

• DNA replication extremely accurate – low rate of errors • Some chemicals and radiation can damage DNA, changing the nucleotide sequence
• DNA repair systems correct errors
• Unrepaired errors in DNA – MUTATIONS!! • Mutations in the germline are heritable

Question 5

The frequency of alleles

Answer 5

•The frequency of alleles can be measured by many methods including DNA sequencing
-The frequency of alleles can be calculated: (number of homozygous x 2) + number of dizyous/ the sample size
• Allele frequencies can vary over time or in space.