Courtesy The Telegraph
Have you heard people say "Oh, it's all in the genes!" They may be
referring to physical traits such as your eye color that you have
inherited from
one of your parents or grandparents. Genes, as you know, are passed
down from one generation to next, and influence how we look, act and
even the diseases we may be prone to.
When the human genome -- the entire genetic sequence that makes us what
we are, was mapped out in 2001, it generated a lot of excitement (read
our previous article
here).
We now knew exactly which genes controlled what features, and where
these genes were located on the thread-like structures called
chromosomes inside our body cells. Sounds great, doesn't it..
.. but there was a dilemma
 |
| Humans have 23 pairs of chromosomes; Gene Chromosome = Genome | |
You see, scientists had identified 21,000 genes that make up our entire
genetic sequence. These genes produce enzymes and proteins that keep
our body functioning. However, chromosomes have tons of DNA (
Deoxyribo
Nucleic
Acid)
which are not part of the active genes. We had only understood 3% of
all the DNA in the human genome. What was the purpose of the 97% of
unused DNA? Scientists had no logical explanation and they called it
Junk DNA.
The ENCODE project, led by 400 scientists from all over the world, has
been trying to shed light on this junk DNA. Recently they announced a
breakthrough. These seemingly
unused DNA are
actually the main control centers (or switches) that control how our
genes work. Scientists have discovered 4 million such gene switches in
the junk DNA, which decide which genes to turn on in which cells, and
how much protein and enzymes the genes should produce.
Why is this important?
We can finally explain how cells that look the same to start out with
in an embryo, change to become liver cells or brain cells? Groups of
gene switches work together to turn on the appropriate genes.
The biggest implication of this breakthrough is in our understanding of
diseases. When scientists compared the genome of a healthy person with
that of a person with say Type 2 diabetes, there were some differences
in an unused section of the chromosome that was located far from the
gene under question. Now, they know that these unused sections are the
switches that might be disrupting the gene's normal behavior.
There is still a lot more that needs to be understood before we can
find a cure for diseases. How do these switches work? How many switches
control a single gene? Can the switches be altered to treat a disease?
It is an exciting time to be in medical research - if you love
biology!
link
Task 1. Read the article and choice True, False or No information.
- Many people thought that DNA was too simple to explain the vast diversity of life on our planet.
- Genes influence how we look, act and even the diseases we may be prone to.
- Chromosomes have tons of DNA which are part of the active genes.
- Today DNA is used is understand and cure inherited diseases, create genetically-engineered medicines.
- Scientists had identified 21,000 genes that make up our entire genetic sequence.
- Scientists had understood 97% of DNA.
- Scientists called unused DNA "Junk DNA".
- DNA had only different amounts of the four bases (A,C,T,G).
- Junk DNA are actually the main control centers that control how our genes work.
- Groups of gene switches work together to turn on the appropriate genes.
