Back in 2003, Scientists completed the sequencing of the human genome, or genetic blueprint of life, which holds the keys to transforming medicine and understanding disease. Key findings of genome sequences include:
1. There are approximately 20,500genes in human beings, the same range as in mice. Understanding how these genes express themselves will provide clues to how diseases are caused.
2. The human genome has significantly more segmental duplications (nearly identical, repeated sections of DNA) than other mammalian genomes. These sections may underlie the creation of new primate-specific genes.
3. At the time when the draft sequence was published fewer than 7% of protein families appeared to be vertebrate specific. (Source 1)
However, they also found that whether you hail from Surbiton, Ulan Bator or Nairobi, your genetic make-up is strikingly similar to that of every other person on Earth. All humans are 99.9 per cent identical and, of that tiny 0.1 per cent difference, 94 per cent of the variation is among individuals from the same populations and only six per cent between individuals from different populations. (Source 2)
Then why identical twins who have the exactly the same DNA have different physical figure (one is aged than other). Or why one member of a pair of identical twins can develop bipolar disorder or asthma even though the other is fine.
The answer lies to a new science called epigenetics. At its most basic, epigenetics is the study of changes in gene activity that do not involve alterations to the genetic code but still get passed down to at least one successive generation. Epigenetic factors, the chemical markers that attach to genes and affect how they are expressed — in some cases by slowing or shutting the genes off, and in others by increasing their output. These epigenetic changes — which accumulate over a lifetime and can arise from things like diet and tobacco smoke — have been implicated in the development of cancer and behavioral traits like fearfulness and confidence, among other things. Epigenetic markers vary widely from one person to another, but identical twins were still considered genetically identical because epigenetics influence only the expression of a gene and not the underlying sequence of the gene itself. (Source 3)
Some researchers did a favorable outcome of epigenetic experiment on mice. Duke University oncologist Randy Jirtle and one of his postdoctoral students, Robert Waterland, conducted an elegant experiment on mice with a uniquely regulated agouti gene — a gene that gives mice yellow coats and a propensity for obesity and diabetes when expressed continuously. Jirtle’s team fed one group of pregnant agouti mice a diet rich in B vitamins (folic acid and vitamin B12). Another group of genetically identical pregnant agouti mice got no such prenatal nutrition.
The B vitamins acted as methyl donors: they caused methyl groups to attach more frequently to the agouti gene in utero, thereby altering its expression. And so without altering the genomic structure of mouse DNA — simply by furnishing B vitamins — Jirtle and Waterland got agouti mothers to produce healthy brown pups that were of normal weight and not prone to diabetes. (Source 4)
So, if gene expression can be changed through lifestyle changes, removing the breast just because having BRCA1 gene is a wise choice? Natural law say that Countless millions of women carry the BRCA1 gene and never express breast cancer because they lead healthy, anti-cancer lifestyles based on smart nutrition, exercise, sensible sunlight exposure and avoidance of cancer-causing chemicals. What we need to address here is that removing healthy organs from your body is not healthy choice, implementing anti-cancer lifestyle is. We shouldn’t give up your hope that you will be healthy even though your parents have diabetes, heart disease, or cancer. You can chose to live healthy. (source 5)
Source 1 – Wkipedia http://en.wikipedia.org/wiki/Human_Genome_Project
Source 3 NYtimes http://www.nytimes.com/2008/03/11/health/11real.html?_r=0
Source 4: Time magazine http://www.time.com/time/magazine/article/0,9171,1952313,00.html