11 September 2012

3 minute read

What is a SNP chip?

It is a small sliver of glass, about the size of a finger-nail, into which are etched a very large number of very small pits. Each of these hold a tiny amount of DNA, which has been extracted from the tissue sample of an animal or plant, and can be 'read' by a DNA sequence-reading machine.

When it was invented in (around 2000), it only carried a few hundred pits for DNA, now it can carry millions. Making the chip and the machine to read it cost millions. Now the total cost of making and reading one is down to around $50.

It has been developing at the fastest rate if any technology ever invented. If cars were improved at the same rate everyone would have top of the range Mercedes-Benz cars for a couple of dollars each. Next year they'd be a few cents each.

How is it used by a sheep or cattle breeder and how does it help their business? What does it allow them to do that they couldn't do in the past?

It's really simple for a sheep or cattle breeder. if they want to get DNA or genomic information on an animal, they simply take a hair or other tissue sample (probably using a blood card), and send it off to be read. teh results then get combined into wither BREEDPLAN, LAMBPLAN or MERINOSELECT breeding values.

The information the chip conveys can include pedigree testing, test for horn/poll status, and/or traits like growth rate or eating quality. And these different types of information can all be included on just one chip!

That last step is important becasue almost always a breeder will get a more accurate picture of their animals' genetics merit by adding performance data in the animals and their relatives.

What's the next 'big thing' for the SNP chip? Where to from here?

The next version will be used to work out the actual sequence of each animal's genome - its actual DNA sequence, rather than simply testing for lots of markers scattered through that sequence. That will make the DNA test result more accurate.

Will we hear more of the SNP chip in the future?

SNP chips will become as ubiquitous as computers or iPhones. They will be part of our medical system, be used to help breed better animals and plants.

One thing that is really important to stress is that while it is a very smart piece of technology, for it to be useful, there has to be lots of good data on the traits evaluated. That means an ongoing collection and calibration of performance and pedigree information from an elite nucleus of animals.