Wednesday, June 25, 2008

"DNA 101 - Genetics for Beginners" Program Summary

Do you remember those excellent teachers and professors when you were going to school - how they could explain a complex subject so that you could understand it, and inject some humor and fun into the topic besides? That's what it felt like, to me, at the CVGS Program Meeting today at the Library.

Dr. Stephen Baird (program summary and curriculum vitae here) presented "DNA 101 - Genetics for Beginners" at our meeting today and it was like going to class again and enjoying it (I admit that I loved many of my science classes when I was in school!). His handout was a glossary of terms used in his presentation for handy reference. His presentation was beautiful - a PowerPoint done the way I like them - large print, some understandable charts, no flash graphics, etc.

I can't go point-by-point in this summary - suffice it to say that he touched on the basic history of genetics and DNA from Mendel to the present, and put it in terms that we could relate to. For instance, human beings have 23 pair of chromosomes, 30,000 genes and 3 billion base pairs, and are, at most, 0.1% different from each other. Humans and chimpanzees are about 2% different from each other in DNA terms.

After describing the chromosomes, the genes, and the DNA base pairs, Dr. Baird described the global phylogeny of all species (how and when certain species occurred and from what they were mutated), the different haplogroups of humans (those with the same genetic markers), and how they spread out of Africa into all of the continents with an approximate time frame. He explained why the Y-DNA and mitochondrial DNA (mtDNA) are important to human genetic testing for genealogy research - the Y-DNA being passed from father-to-son, and the mtDNA being passed from mother-to-child.

Many of the technical charts that he used were obtained from the web site. Some of them were obtained from the tutorials at and He used his own DNA test results to show charts similar to those in this downloadable tutorial for presentations. Dr. Baird also described the relative costs of doing 12, 25, 37 or 67 markers for Y-DNA testing and for doing the basic and more advanced mitochondrial DNA testing.

At the end of the hour-long presentation, which seemed to go very fast (for me, at least!!), Dr. Baird played his guitar and sang the "Ballad of Gregor Mendel" from one of his CDs (available for sale at It was a wonderful end to the talk. Then the questions began...and lasted a good 20 minutes!

We had 48 people in attendance, including 15 visitors from all over San Diego, and even one from Orange County. This was one of the very best presentations and meetings that we've had in my six years on the CVGS Board.

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