Scientists complete decoding human genome

• In February 2001, researchers have released the first set of the human genome sequence.
• Twenty years later, researchers have finally deciphered it all filling the gaps in the long list of errors in previous versions and changing our view of human DNA.
• Scientists from the Telomere to Telomere (T2T) Consortium have reported the most complete sequencing of the human genome until now.

Human Genome Project:

• The Human Genome Project (HGP) started in 1990 as a collaboration between international researchers whose shared goal was to map and understand all the genes of a human being.
• All of a person’s genetic material taken together, including all the genes and other genomic elements, constitute their “genome.”
• This study adds 200 million base pairs to the last draft of the human genome that was published in 2013.

It aimed to decipher the human genome in three major ways:

• Determining the order, or "sequence", of all the bases in our genome's DNA
• Making maps that show the locations of genes for major sections of all our chromosomes
• Producing what is called linkage maps, through which we inherit the trait
• The results come with the caveat that about 0.3% may still have errors, and that among the sex chromosomes, only the X chromosome has been sequenced.
• The study has discovered 115 new protein coding genes.

Human Genome:

• It is made up of 23 chromosome pairs with a total of about 3 billion DNA base pairs.
• There are 24 distinct human chromosomes: 22 autosomal chromosomes, plus the sex-determining X and Y chromosomes.
• Chromosomes 1-22 are numbered roughly in order of decreasing size.
• Somatic cells usually have one copy of chromosomes 1-22 from each parent, plus an X chromosome from the mother and either an X or Y chromosome from the father, for a total of 46.
• There are estimated 20,000-25,000 human protein-coding genes.

Protein-coding genes:

• They are DNA sequences that get transcribed on ribonucleic acid (RNA) as an intermediate step before protein synthesis.
• These proteins define the characteristics of the person. These proteins carry out the instructions encoded in the genes.

Significance:

• The new findings will help provide a better understanding of the human body.
• The technology used by the Telomere to Telomere Consortium used sequencing technology that could scan 20,000 base pairs at one go as against the few hundred pairs previously.
• The genome draft will form a standard for comparison in future sequencing attempts