Advent, chromosome by chromosome

By Grant Jacobs 07/12/2013

Why not count down the days of the advent chromosome by chromosome? It’s a great idea and the Royal Institution’s implementation of it is excellent, try it.

When you visit their advent website, you’ll see a karotype,* with a microscope lens in middle.


We have 23 pairs** of chromosomes: one pair of sex chromosomes (XX in women, XY in male) and 22 pairs of autosomes (non-sex chromosomes) numbered 1 to 22.

We also all have a small organelle that is involved in ‘energy’ processing in our cells, the mitochondria. It has it’s own little chromosome, known for being passed down only from our mothers,*** that is counted as the 24th chromosome for this advent calendar.

Move the lens around to locate each day’s calendar (you can change the focus, too). Days that haven’t yet come to pass aren’t labelled.

Each day has a short film exploring part of that chromosome and interesting genetics associated with it. If you’re thinking amateur science videos, don’t. Think more BBC documentary.

From their blurb for the calendar on the trailer (shown below),

Highlights include geneticist Dr Adam Rutherford exploring what ‘junk’ DNA is, a light-hearted look at male baldness with former Christmas lecturer Mark Miodownik, and a visit to Alison’s lab at the University of Oxford to learn more about the genetic control of ageing. We’ll explain Nobel Prize winning science, take a trip to the zoo and delve into the mysteries of ginger hair.

The series will also raise awareness of several rare and not-so-rare genetic disorders such as Alkaptonuria (AKU) as well as other more well known diseases with a hereditary link including breast cancer. Through interviews with experts and personal stories we’ll reveal the genetic secrets behind these conditions and highlight the latest cutting-edge research to help prevent, treat and manage them.

You can watch the trailer for their advent calendar below,

You’ll spot that links to the Royal Institution’s Christmas lectures are at the bottom of the advent calendar page.


* I briefly described karotypes in my second Not Just DNA article.

** There are rare cases of ‘extra’ chromosomes, typically associated with disorders. Down Syndrome is probably the best known example, usually associated with the person have 3 copies of chromosome 21. There are also people with 3 or more sex chromosomes. Loss of a chromosome is typically associated with illness.

*** This is exploited in tracing the origins of humans, for example in the famous ‘African Eve’ research that showed all humans originally came from Africa.

Other articles on Code for life:

Is a genome enough? (Not Just DNA #1)

What does a chromosome look like? (Not Just DNA #2)

The scale of cellular life and compacting chromosomes

Coiling bacterial DNA

Temperature-induced hearing loss

The inheritance of face recognition (should you blame your parents if you can’t recognise faces?)