AtoZ: G Is For Genes
By Katie Giles
If your genes make you look fat, then I’m sorry but there’s not a lot you can do about it. Your own unique genome is the product of a toss of the chromosomal coin, a random mixing of your parents’ DNA. In other words, if you want someone to blame for your short-sightedness, balding pate or big feet, look no further than Mum and Dad.Genes are regions of DNA (a molecular coding message that consists of A, C, G and T bases and is common to all living things) carried on structures called chromosomes (in pictures). Most humans carry 23 pairs of chromosomes – one pair determines whether we’re female or male and the rest code for pretty much everything else. All they actually do is provide a template for making proteins (DNA to protein explained).
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The Human Genome Project revealed that we have many fewer genes than expected. Humans weigh in with somewhere between 20,000 and 25,000 genes – only about twice as many as the fruit fly, and fewer than both mice and rice plants (comparison of gene numbers).
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In theory (well, Darwin’s anyway) humans are getting better all the time. Over thousands of generations only the fittest have survived; those of us whose genes produce the best proteins do best and have most offspring. We are, in fact, highly evolved specimens. This may be difficult to believe if you’ve ever witnessed a typical Saturday night in your local city centre, but on the whole we’ve moved on from grunting at each other in caves and going out clubbing.
However, it’s not all about our genes. How people develop is a case of nature and nurture, so your upbringing and childhood environment help to shape who you are. If you feel fate has given you a raw deal in the inheritance lottery, don’t panic – just hope for a nurturing family life that will iron out any genetic imperfections.
Monozygotic (identical) twins are nature’s own genetic clones. They have identical genomes and are therefore useful to scientists looking to explore the influence of both genetic and non-genetic factors on determining who we are. They’re also great as freaky extras in sci-fi series, hot-pant-wearing Romanian ‘singing’ acts and East London organised-crime bosses.
An important thing to remember when you’re ready to add your own branch to the family tree is to take a leap into the deep end of the gene pool. Breeding is something definitely best not kept in the family. Unless, that is, you have a particular use in mind for those webbed feet or extra digits.
In a nutshell: As easy as AGC (and, err, T)
Not to be confused with: denim clothing, genies, English mid-90s indie-rock quartets
Learn more at the Genetic Science Learning Center or simply better yourself with more top science:
- A to Z - Amino Acids
- How it works - Stem cells
- Everyday things - Tattoos
- Games - Geography quiz
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