Authors

Brief Overview:

Lactose tolerance is the ability of human adults to consume milk products without uncomfortable side effects. It is due to the persistence lactase gene expression into adulthood and is a relatively new trait in our evolutionary history. It a particular interesting trait to study because involves a SNP that does not change amino acid composition of the lactase protein, but rather appears to enhances its transcription and because it provides an example of convergent human evolution. Although lactose tolerance is completely correlated with a C/ T variation about 14 kb upstream from the lactase gene in Northern Europeans, this SNP is not highly correlated with lactose tolerance in African populations. In fact, different SNPs conferring lactose tolerance seem to have arisen independently in three different African populations. Thus, the appearance of lactose tolerance appears to be one of the first examples of convergent evolution in humans, where the trait arose at different times and independently indifferent human populations. Our goal is to utilize lactose tolerance as case study in which students will learn about SNPs, SNPs databases, and convergent evolution. Also we hope to develop a lab exercise demonstrating how the SNP could be typed (PCR and RFLP), either in silico or using students’ own DNA in a wet lab.  

Resources and References:

ALlele FREquency Database
Lactose Tolerance in East Africa Points to Recent Evolution-Newspaper article
International HAPMAP project
Ensembl SNPview
NCBI SNP database  

Attachments

- Lactase_review.pdf
- Finnish_article_2003.pdf
- Lactase_Study_20071.xls
- PCR_primers.pdf
- SNPScope_Mar08.ppt