Let me count the ways…

It is not generally considered flattering to be compared to a snail, nor indeed to that other unloved member of the mollusc clan, the slug.

Both are slimy and have somewhat ambivalent private lives. ("Hermaphrodite? Huh! I reckon you’re just commitment phobic.") They are inclined to pop up unpredictably at inconvenient moments and in unwanted places. They eat more food more quickly than one would think possible. Their toiletry habits leave a lot to be desired. They have a herd mentality, being either entirely absent from the scene or present only in slowly swarming creeping hoards. They live in mobile homes or have no fixed abode - and in either event prefer to squat in yours without paying rent. They devour one's obsessively nurtured and cosseted seedlings overnight without even touching the weeds. They are rather spineless and retreat into themselves at the first signs of confrontation. Describing oneself as having snail-like (slow, shy, short-sighted) or slug-like (creepy, slothful, hiding under paving slabs) tendencies is unlikely to land one a dream job.

No, on the face of it, slugs and snails don't have an awful lot going for them.

But hold your boot before you next stand on one, for you are standing on a relative. New research has shown that humans and snails share some genetic material. And whilst we have probably all met a few people for whom this was readily apparent without the slightest need for a microscope, it is actually readily apparent in all of us.

Unless you do actually resemble one of Picasso's studio models (as I do in the mornings and on occasional late nights), the chances are that your face and your body are quite symmetrical. Most of us have most of our features and limbs arranged in more or less matching opposite pairs. Eyes, hands, knees, arms, legs, ears, fingers, thumbs, elbows, ankles, toes. Those elements of which we have only one - noses, necks, belly buttons, mouths and such - are conveniently lined up down the middle in a sort of peace-keeping middle line shared pretty much equally between left and right.

But it's a whole different story on the inside. Safely hidden away from the judgemental eye of the external beholder, our bodies are a riot of lopsidedness, unilateral decision-making and idiosyncratic location selection. Your stomach tends to the left, your liver to the right; your heart to the left, your appendix to the right. Being the ego-centric organ it is, your brain occupies both sides of your skull but divides its labours in a partly bilateral fashion whilst also choosing to take responsibility for the operational control of the opposite side of the body.

Apparently, this seemingly haphazard blue print is essential for our well-being and not just a case of the universal architects and builders having got the plans muddled up. And it is in the asymmetry at the genetic level that snails are indeed our relatives. Should you care to look closely, some species of snails have shells that coil to the left, others to the right; even though we have no shells other than those of our own making, it is this tendency to asymmetry that unites us.

As our last common ancestor lived about 600,000,000 years ago there's probably no pressing need for rolling out the banners and throwing a big welcome home party. But maybe a reason to think a little more kindly about the slimy squatters in your flower bed?

If you want to find out more: http://www.guardian.co.uk/science/2009/apr/15/genetics-embryos-and-stem-cells