STEM News: The Quest to Sequence the Human Genome
Genomics
Genomics is the study of genomes, especially relating to the structure, function, evolution, and mapping of genomes. A genome is an organism’s full set of deoxyribonucleic acid or DNA. DNA is made up of 4 unique chemical bases called adenine, thymine, guanine, and cytosine. The order of these 4 bases determines the proteins our DNA makes and therefore the function of each part of our DNA. Each organism has a unique set of DNA, with differently ordered chemical bases, that acts as instructions for development, survival, and reproduction. Despite DNA being unique, 99.9% of our DNA is identical to any other human with the average person only having a 1-3 base difference from someone else. Even such a small difference in 3 bases can cause differences in eye, skin, and hair colour. Genomicists analyze the double helix structure of DNA and the individual bases found within to learn more about the function and evolution of certain genes. This research is important to understand more about every part of human existence from the creation of proteins in cells, to genetic disorders. The sequencing of DNA is one of the biggest projects involved in understanding how humans work on a cellular level. It is especially important because even single-base differences can cause people to be more susceptible to certain diseases. One notable project that was successful in sequencing large segments of DNA was the Human Genome Project.
The Human Genome Project
The Human Genome Project began in 1990 as a United States government project led by the National Center for Human Genome Research with the help of researchers from around the world. The project was completed in 2003, and it was able to map the majority of the human genome with impressive accuracy. Along with creating a draft of the human genome, the project also created drafts for mouse and rat genomes and identified over 3 million single-base variations in the human genome. To decipher the genome, the project determined the order of the chemical bases in our DNA, mapped the location of genes on our chromosomes, and produced linkage maps of how genetic diseases can pass through generations. Since successfully determining the chemical bases of billions of base pairings of DNA, the Human Genome Project has continued to investigate the social, ethical, and legal implications of obtaining such knowledge.
Recent Additions to the Human Genome
Despite the 2003 Human Genome Project being able to map the majority of the human genome with impressive accuracy, there were still parts of the genome to be sequenced. Between 2003 and 2013 many more stretches of DNA were sequenced leaving the genome 92% complete. Earlier this summer, the international consortium, Telomere-to-Telomere (T2T) Consortium, announced it had sequenced 115 new protein-coding genes or 200 million base pairs bringing the total to 19,969 protein-coding genes sequenced with over 3 billion base pairs. Overall, the impressive addition to the draft of the human genome increased the number of sequenced genes by 4.5% to 3.05 billion with approximately 99.97% accuracy.
Future Genomics Projects
Just months after the release of a paper describing the findings of the T2T Consortium, new research is already being planned, and new discoveries are being made public. T2T Consortium has announced plans to team up with the Human Pangenome Reference Consortium to sequence 300 more genes from around the world and continue contributing to the draft of the human genome. Just this week, research was published that only 1.5-7% of the human genome is uniquely human. Without the draft of the human genome, this discovery and others like it would have been impossible. Every step towards fully sequencing and understanding the human genome will allow genomicists to understand more about evolution, biology, and health, among other fields.
Sources:
National Human Genome Research Institute Home (National Institute of Health) https://www.genome.gov/
Human Genome Project (Britannica) https://www.britannica.com/event/Human-Genome-Project
A complete human genome sequence is close: how scientists filled in the gaps (Nature) https://www.nature.com/articles/d41586-021-01506-w
Image Source:
Image by Arek Socha from Pixabay
