The DNA-Team acteristics,’ adds Tinch.
QUANTUM LEAP Genomics is really where Landcatch is raising the bar in terms of technology. ‘Genomics is the quantum leap, the game changer,’ says Neil Manchester, ‘and we’re leading the world in the development and adoption of this technology. Using genomics, not only can we find the families that have the traits we are selecting for, but the individual males and females within that family. With genomics we can ensure that the salmon equivalent of Brad Pitt finds his Angelina.’ In March of this year Landcatch launched onto the market a high den- sity SNP chip for salmon breeding, the result of a three-year project. This commercially available genomics tool is a very sig- nificant piece of technology that allows you to look for genetic associations for the traits you are interested in using 150,000 individual milestones. ‘Where once upon a time
you would look at half a dozen, twenty markers at most,’ explains Alastair Hamilton, Head of Molecu- lar Biology, ‘the technology has moved on to a point where for some spe- cies there are chips with millions of markers. We decided that for the salmon genome 150,000 markers would give us the resolving power we needed.’ The chips are essentially specialised glass wafers, each of which has a fix to it of around 286,000 of the
variant DNA sequences, which corresponds to the 150,000 markers. The preparation of the chip begins by taking short sequences the DNA of 100 fish from diverse popula- tions within the Landcatch broodstock at multiple, random points throughout the genome.
The sequences are then compared across mul- tiple individuals to find the points in the genome where two sequences differ by a single base – which correspond to a significant difference in salmon. One salmon might carry one variant, one salmon might carry another, and one salmon might carry both. ‘We identified about 12 million of these differ- ences,’ explains Hamilton, ‘and using a data filtering process we identified the few hundred thousand that looked most promising for incorporation onto the chip.’
The unknown DNA of the salmon you are investigating is then added. If this salmon DNA finds a perfect match to any of the sequences on the chip, it will hybridise – stick to it. A fluoresecent dye allows the hybridised DNA you are investigating to show up as an array of pixels indentify- ing the various matches. ‘This is a major step for-
ward, we’ve moved salmon breeding forward to the next generation,’ says Tinch. ‘It’s like moving from ana- logue to digital television – it’s genetics, but digit- ally-based – so we’re able to make far more accurate
Landcatch’s biggest success was locating the gene for IPN resistance
www.fishfarmer-magazine.com 33
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68