The Cajun Genetics Project — 2017
As I mentioned in my biography, I am majoring in Biology and Psychology here at UGA. For this section of my project I wanted to incorporate my studies with my family’s history. Luckily, because I’m a college student and have limited funds, my uncle took a DNA test through Acestry that determined how many types of different DNA my family has in their history. I didn’t think much of it until last semester when I took Genetics. This class was by far one of my favorite classes, not only because my teacher tried to make it as interesting as possible, but because I’m in love with how intricate and amazing our bodies are.
Humans have 2 sets of 23 chromosomes in every cell of their body. As you probably know, chromosomes are supercoiled versions of DNA. DNA stands for deoxyribonucleic acids. These nucleic acids bind together to create DNA and the famous double helix structure that everyone pictures when you think of DNA. What is incredible to realize is that there are about 3.2 billion base pairs in the human genome which means there are about 6.4 billion nucleic acids in each one of our cells. It has been proven that if you stretch out all the DNA in one cell it reaches 2 meters long! So, when they say “supercoiled” they really mean, SUPER coiled.
In 1990 geneticists started the Human Genome Project. This project was initiated in order to sequence every base pair in the human genome. It was estimated to take 15 years and cost 3 billion dollars to complete the process. That means it would cost about $1 to sequence each base pair! Unfortunately, by 1998, more than halfway through the time and money spent, they had only sequenced 4% of the genome. Clearly, they needed a new plan.
The technique they had been using was called “clone-by-clone sequencing.” This process was brutally slow and technically difficult. Basically, the idea was to divide the DNA by each chromosome, cut each chromosome into tiny pieces, clone the pieces, and then sequence each piece at a time. Although it sounds like a reasonable way to go about sequencing each base pair, it was almost impossible to re-align each section of DNA into the correct original order of base pairs.
The new technique proposed was called “whole genome shotgun sequencing.” This technique was similar to the original technique except for one very important factor. Instead of cloning one time, each base pair was cloned at least three times. In doing this, they could see where the DNA would overlap and easily align each section into the correct order. So, after 8 years of only completing 4% of the genome, they completed sequencing 96% of the genome by 2000 using only 300 million dollars! — The government could have saved a LOT of money.
This project allowed geneticists to understand what genes have what functions. There are numerous computational algorithms that can now look at DNA and transcribe/translate the base pairs into polypeptide chains, which make up proteins. Since we already know certain proteins and their functions, we can now find them on the human genome. Scientists have discovered about 61% of the human genome’s functions.
Additionally, there was a project completed called the “1000 Genomes Project.” This project compared 2,504 samples from 26 worldwide populations. They found that each genome differs from the reference at 4–5 million places that we now call “SNPs” — pronounced ‘snips’ — (single nucleotide polymorphisms). This project proved that the highest diversity in genetic information is in Africa and provided insight into the evolutionary history of humans.
When scientists realized that each individual has SNPs in their genome, and that these SNPs are passed on through generations, they started the “International HapMap Project.” This was designed to identify common genetic variation among different populations. Once millions of different SNPs were identified, they could make SNP microarrays, or “SNP chips,” that allow an individual’s DNA to hybridize to the chip and determine which SNPs they did or didn’t have. With these SNP chips we can learn a humongous amount about an individual’s DNA including, disease risk, carrier status, familial traits, familial relationships, drug susceptibility, and ancestry. SNP chips can do this without spending nearly as much money as it would cost to sequence each person’s entire genome.
SNP chips are what 23andMe and Ancestry use to determine all the information they give you once you pay for these types of DNA-involved programs! My uncle didn’t do the expensive version that involved disease risk, drug susceptibility, etc., but he did choose the option that tells you how much different type of DNA is in your own DNA! He sent me his information and this is what is pictured above.
What’s strange is that his DNA only showed 8% of Western European comparison and 45% of Great Britain comparison. This means that although our family can be traced back to the French Acadians, only 8% of our DNA provides that evidence. Clearly, generations upon generations have mated with those of Great Britain descent as we’ve become more Americanized over the years. However, these results are also interesting because if you look up the origins of the name “Aitkens” you will find that it is of Scottish Descent and Scotland is in Great Britain. Nonetheless, it does say that our DNA hybridized to those of early settlers of the deep south which, as we know, is true of our roots in Louisiana.