What are SNPs?
A specific nucleotide position on the chromosome that is not 100% identical between different human individuals. They appear due to random point mutations, often due to errors in DNA replication that are not repaired. Random mutations happen all the time, and only those single nucleotide variations that appear greater than 1% frequency in the human population do we call “SNPs.
Need additional review? Here’s a great reference.
There are more than 11 million known SNPs, many of which are associated with human diseases or other traits. Those that affect human phenotypes can be broken down into 2 main categories, non-causative SNPs and causative SNPs. Non-causative SNPs are not the reason why certain people have a trait or not because they do not change proteins or gene expression. Rather, they are nearby on the chromosome to other variants that do cause the trait and are therefore inherited along with the mutation that causes the disease only because of their proximity. Causative SNPs are SNPs that change a protein sequence or alter gene expression in a way that directly contributes to the disease or other trait.Have you thought about using a service from companies like 23andMe or Ancestry to look at your DNA and assess your health risks or trace your ancestry? These companies don’t sequence all of your nucleotides but instead sequence a proprietary collection of 100s or 1000s of SNP regions only. Sometimes the information these companies can collect can be used to solve crimes, such as in the case of the Golden State Killer (Links to an external site.).The Lab Assignment: Find SNPs in a trait that you are interested in learning more about
- Think of some traits you might be interested in: anything from hair color or eye color to a specific disease. Follow the steps in the activity below to identify SNPs associated with these traits and find where in the DNA they are located.
- Maybe they are part of the sequence of a gene (or not)
Maybe they are causative (or non-causative)
- In this activity you will try to come to a conclusion about a specific set of SNPs of your choosing.
Click the link below to open google doc and complete the activity. You can’t edit the google doc directly, you will first have to make your own copy (File > Make a copy) that you can edit.SNP lab activity
here is the file for the questions SNP lab activity