Monday, March 09, 2015
My ABGT teleconference-based pieces all had a theme of library preparation. Library prep has never been as flashy as instrument performance, but is clearly critical. A library-free sequencing technology remains a distant dream, so DNA (or RNA) must go through a series of preparative steps prior to being loaded on the sequencer. The dominant library prep molecular biology for clonal sequencing systems consists of shearing the DNA mechanically, making flush ends with a repair mix, adding 3' runs of A and then ligating primers and finally using PCR to amplify the material.
Mechanical shearing can be replaced with enzymatic shearing (or perhaps even chemical, though I'm unaware of chemical shearing being used in production). For RNA of different sorts,
some upstream steps are added to convert the RNA to DNA, perhaps with a depletion at some stage of hyperabundant species such as rRNA. This conversion may, with different levels of success, mark which strand was sense and which antisense. The transposase-based Nextera protocol represents the most drastic departure from this paradigm, enzymatically eliminating all the steps prior to PCR.
Saturday, March 07, 2015
Last night was the season five finale of the Gold Rush, which I confess is one of the few television programs that I have been watching routinely near their airing schedule (the other is The Simpsons, which is a father-son bonding experience). Now, writing in a blog mostly about science that you watch something on the Discovery Channel is a bit of a bold act, given its many panderings. The network annually features Shark Week, that has been roundly criticized for its sensationalized portrayal of these magnificent creatures. It also features shows which purport to show individuals routinely engaged in felonies and in one case claiming to document a violent subculture in a pacifist religious community, the Amish. I grew up near the Amish Country of Pennsylvania; if anything like that ever existed the Philadelphia papers would have had a field day. Gold Rush itself, and a second gold show which I've developed a fondness for, Bering Sea Gold, has shortcomings that are obvious and painful. So why am I hooked?
Wednesday, March 04, 2015
I've been asked several times recently about rumors coming out from BGI. They've started claiming they have a super sequencer which will radically beat Illumina's offerings on both cost and accuracy. The recent 10K Genomes meeting apparently had a quick talk from BGI which led to some limited Twittering, and judging from this Mendel's Pod interview at least one person believes the buzz (though the same individual quotes a price per PacBio human genome that high by at least a factor of 25). . The claim is that this summer at ESHG BGI will release two boxes, one a benchtop model which I haven't seen any details on, and the other claimed to offer throughput superior to a HiSeq with better accuracy. What might be backing up these claims?
Saturday, February 28, 2015
Rounding out my remote coverage of platform news from AGBT, the Ion Torrent team also lent me some of their time (and at risk of sounding obsequious, I do greatly appreciate this -- vendors have almost no down time at these events) to touch on some of the topics I I wrote about in my Ion history and speculation piece.
Friday, February 27, 2015
Perhaps the heavily anticipated launch at AGBT this year is the library prep instrument for 10X Genomics. This Bay Area startup made a huge splash at the beginning of the year by announcing a monster ($55.5M) financing. A member of my professional network had been part of the early team and had given me very minimal hints at last year's AGBT, so I've been eagerly awaiting details for a long time. Several members of 10X's team were kind enough to chat with me by phone yesterday with the proviso that I hold off on launching this piece after their talk today at the conference (interestingly, I had crossed paths with all of them in some previous setting). Also, they sent me some promotional materials and permitted me to post some clips from them. Now, the GemCode system is officially launched, with orders being taken now and devices planned to be delivered in early Q2.
Wednesday, February 25, 2015
The 2015 AGBT conference started out today. A few hardware makers have let me chat by phone with members of their team, since they're there and I'm not. Tonight's dispatch is from a chat with Illumina focused on their now launched NeoPrep library preparation instrument