1. The ABC’s of DNA
Barry Bowman

2. The Central Dogma of Molecular Biology

5. DNA Structure

8. In humans our DNA is in 46 pieces, our chromosomes
One complete set DNA molecules makes up a “genome.”
This has 3 billion base pairs, ~25,000 genes.
Over 95% of our DNA is not in genes.

11. The Genetic Code Three letters make a “word” (specify an amino acid)
ATG means start, with the amino acid methionine
TAA or TAG or TGA means stop
DNA
ATGCGTTGCGCTCAGTGCCACACCCTTGAGGAGGGCGGCGGCAACTAA
RNA
AUGCGUUGCGCUCAGUGCCACACCCUUGAGGAGGGCGGCGGCCAACUAA
PROTEIN
MetArgCysAlaGlnCysHisThrLeuGluGluGlyGlyGlyAsn

16. Ancestry can be determined by SNP analysis
SNP = single nucleotide polymorphism
a “snip”
CGGGTTAAGCTGCGCCAATCGCGTATAGGCTAATTTTTGCTAAAGGGCGCGTGATGCAA
* * * *
CGGGTTATGCTGGGCTAATCGCGTATAGGCTAATTTTTGCTAAAGGGCGCGTTATGCAA
These changes arise by mutations in the DNA.
Most occurred thousands of years ago.

17. SNPs Humans are genetically >99 per cent identical: it is the
1% than make us different.
Much of our genetic variation is caused by SNPs.
Each of us has a unique genotype that typically differs in about three million nucleotides from every other person.
SNPs occur about once every base pairs in the genome, and tend to remain stable.
Because only about 3 to 5 percent of a person's DNA sequence codes for the production of proteins, most SNPs are found outside of "coding sequences".

19. Shared ancestry is indicated by shared clusters of SNPs
CGGGTTAAGCTGGGCTAATCGCGTATAGGCTAATTTTTGCTAAAGGGCGCGTGATGCAA 1 2 3 4 5
Person #
“haplotype” is a shared cluster of SNPs

20. Biologists have sequenced the DNA of
thousands of people around the world

21. The Human Karyotype

22. Sally Hemings and Thomas Jefferson Analysis of the Y chromosome
Jefferson’s uncle
Father of Jefferson’s
nephew’s
From Nature,
5 November 1998
Another
Hemings
son

24. DNA tests may examine 1,000,000 Haplogroups

25. Mitochondrial DNA always comes from the mother

26. Mitochondria from the male
do not enter the egg

27. Will DNA analysis fill in the blanks in our family tree?