The wacky world of DNA

The Wacky World of DNA

By Udbhav Relan

Can you roll your tongue? How about your earlobes — are they attached or unattached? We’ve all noticed these differences, and we all know why they exist. Yes, it’s genetics.

We all share about 99.9% DNA with each other. That 0.1% difference in our genetic makeup is what makes us susceptible to different diseases and dictates how we respond to the same drugs. But as with everything else in life, our genes can also go absolutely nuts sometimes. Here are some truly wacky facts about the world of DNA.

Some Basics First

• The human genome contains about 30,000 genes made up of 3.2 billion nucleotide bases

• If you laid your entire DNA end to end, it would stretch from the earth to the moon 6,000 times

• You could fit 25,000 strands of DNA side by side in the width of a single adult hair

• Your genes only make up about 2% of your DNA, while 8% comes from ancient retroviruses

• You share 98% DNA with chimpanzees, 92% with mice, and about 50% with bananas. Yes, bananas

• Red blood cells are the only cells in our body that do not possess DNA

And Now It Gets Really Interesting

• Identical twins who marry identical twins — their children would be cousins, but also genetic siblings sharing identical DNA

• Tetrachromatic women have a mutation giving them four types of cone cells, allowing them to see up to 10 million colours (vs. 1 million for the rest of us)

• Every cheetah alive today is partially a clone of the rest — a genetic bottleneck from near-extinction at the end of the last ice age

• The Fugates of Kentucky had blue-coloured skin due to a rare genetic condition called methemoglobinemia

• Our genes limit our lifespan to about 120 years — the longest documented lifespan is Jeanne Calment of France, who lived 122 years and 164 days

• Mitochondrial Eve — all humans carry genetic material passed down from a single female line extending back ~200,000 years

• Hate broccoli? It may not be your fault — a compound in cruciferous vegetables tastes bitter or insipid depending on your genetic makeup

• “Uberboy” — a child born in Germany in 1999 with a mutation in his myostatin genes was born visibly muscular and was lifting far more than other toddlers by age 4

• Kodinhi village in Kerala has over 250 sets of twins within just 2,000 families — baffling geneticists worldwide

• Red hair and freckles are genetic mutations. The Weasleys were the mutant family all along

• Heterochromia iridum — a mutation causing eyes to have multiple colours, from a slight central variation to completely different colours in each eye

Unbelievable? Believe it!