learning about genetics

This discovery may undercut the rationale behind numerous large-scale genetic studies conducted over the last 15 years, studies which were supposed to isolate the causes of scores of human diseases.

Most body samples used in large-scale genomic studies are saliva or blood. If these samples have DNA that doesn't match genetically to cells in the diseased or affected tissue--which this report suggests is likely--then, the samples may not tell us "the truth" about the DNA makeup responsible for the disease being investigated. Thus, "ambitious and expensive genome-wide association studies may prove to have been essentially flawed from the outset."

Perhaps you've been reading in the news lately about genes "for" autism, obesity, cancer, sudden heart attack . . . . . . and on and on.

What are all these reports about? 

Most of the reports you see are based on genome-wide association studies, or GWAS. You pronounce this acronym: gee wahs.

The genome, by the way, is the full set of DNA (the inherited material) in a human, mouse, yeast, or whatever is being studied. In most interpretations, genomics--the science of genomes--includes the study of environmental as well as genetic information. However, GWAS are usually studies of the DNA of large populations of people with disease X compared with 1) people who don't obviously have the disease or with 2) some sort of DNA standard.

Just in time for the holidays:

Users who accessed AAAGTCTGAC also bought:

• BioPet DNA Breed Identification Kit
• The DNA of Relationships
• DNA Nation iPhone Cover Sticker
• DNA by Bijan for Men -- Eau De Toilette

I couldn't resist playing with Amazon's announcement that it's making the Annotated Human Genome Data available via Amazon Web Services.

Hsien-Hsien Lei of the Eye on DNA blog recently asked readers to define genetics in one simple sentence. I tried, with the following:

Genetics is the study of the operating instructions for life.

To this could be added: Scientists look at how the instructions are passed from one generation to the next, how instructions differ from one living thing to another, and how the instructions work.

For a "young" audience, something modern--operating instructions--could be useful. Note that the second sentence distinguishes the various components of genetic study: inheritance, form, function.