Methods and Products for Analyzing Polymers

Abstract

Methods and products for analyzing polymers are provided. The methods include methods for determining various other structural properties of the polymers.

Description

BACKGROUND[0001]The study of molecular and cellular biology is focused on the macroscopic structure of cells. We now know that cells have a complex microstructure that determine the functionality of the cell. Much of the diversity associated with cellular structure and function is due to the ability of a cell to assemble various building blocks into diverse chemical compounds. The cell accomplishes this task by assembling polymers from a limited set of building blocks referred to as monomers. The key to the diverse functionality of polymers is based in the primary sequence of the monomers within the polymer and is integral to understanding the basis for cellular function, such as why a cell differentiates in a particular manner or how a cell will respond to treatment with a particular drug.[0002]The ability to identify the structure of polymers by identifying their sequence of monomers is integral to the understanding of each active component and the role that component plays within...

AI Technical Summary

Benefits of technology

[0025]The invention relates to new methods and products for analyzing polymers and in particular new methods and products useful for determining the sequence of polymers. The invention has surprising advantages over prior art methods used to sequence polymers. Prior to the present invention no method or combination of methods has come close to achieving the rate of sequencing which the instant invention is capable of achieving. Using the methods of the invention the entire human genome can be sequenced several orders of magnitude faster than could be accomplished using conventional technology. In addition to sequencing the entire genome, the methods and products of the invention can be used to create comprehensive and multiple expression maps for developmental and disease processes. The ability to sequence an individual's genome and to generate multiple expression maps will greatly enhance the ability to determine the genetic basis of any phenotypic trait or disease process.

[0028]The proposed method for analyzing polymers is particularly useful for determining the sequence of units within a DNA molecule and can eliminate the need for generating genomic libraries, cloning, and colony picking, all of which constitute lengthy pre-sequencing steps that are major limitations in current genomic-scale sequencing protocols. The methods disclosed herein provide much longer read lengths than achieved by the prior art and a million-fold faster sequence reading. The proposed read length is on the order of several hundred thousand nucleotides. This translates into significantly less need for overlapping and redundant sequences, lowering the real amount of DNA that needs to be sequenced before genome reconstruction is possible.

[0029]Methods for preparing polymers for analysis are also claimed herein. The combination of the long read length and the novel preparation methods results in a much more stream-lined and efficient process. Lastly, the actual time taken to read a given number of units of a polymer is a million-fold more rapid than current methods because of the tremendous parallel amplification supplied by a novel apparatus also claimed herein, which is referred to as a nanochannel plate or a microchannel plate. The combination of all these factors translates into a method of polymer analysis including sequencing that will provide enormous advances in the field of molecular and cell biology.

[0030]The ability to sequence polymers such as genomic DNA by the methods described in the instant invention will have tremendous implications in the biomedical sciences. The recovery of genetic data at such a rapid pace will advance the Human Genome Project. The methods and products of the invention will allow the capability to prepare multiple expression maps for each individual, allowing complete human genetic programs to be deciphered. The ability to compare pools of individual genetic data at one time will allow, for the first time, the ability to discover not only single gene diseases with ease, but also complex multigene disorders as rapidly as the DNA itself is sequenced.

Problems solved by technology

In addition, only one very incomplete human body expression map using expressed sequence tags has been achieved (Adams et al., 1995).

Current protocols for genomic sequencing are slow and involve laborious steps such as cloning, generation of genomic libraries, colony picking, and sequencing.

Given the multiplicative effect of these unfavorable facts, it is evident that the sequencing of even one genome requires an enormous investment of money, time, and effort.

The main drawback is that there is not continuous loading of the capillaries since a new gel-filled capillary tube must be prepared for each reaction.

Even though there is a substantial reduction in the number of gels run, the washing and hybridizing steps are as equally laborious as running electrophoretic gels.

The major limitation, however, is that the read length is on the order of tens of bases.

Much longer read lengths are physically impossible due to fragmentation of longer DNA at guanidines during the analysis step.

Mass spectrometry sequencing is thus limited to verifying short primer sequences and has no practical application in large-scale sequencing.

These lack the binding sites to hold DNA strongly enough to resist removal by the physical and electronic forces exerted by the tunneling tip.

With difficulty, DNA molecules can be electrostatically adhered to the surfaces.

Even with successful immobilization of the DNA, it is difficult to distinguish base information because of the extremely high resolutions needed.

The main disadvantage is the short read length.

If there is even 1% loss of starting material for each wash, after 400 washes there would be 1.8% of the starting material remaining, which is insufficient for detection.

In practice, exonuclease sequencing has encountered many difficulties in each of the steps.

Sterically, this is extremely unfavorable.

Furthermore, difficult optical trapping is needed to suspend DNA molecules in a flowing stream.

The step is time intensive and requires considerable expertise.

Even a 1% error is significant.

The efficiency of detection has been pushed to the limit and it would be difficult to achieve further improvements.

Probe Up methods would require, for an 8-mer, 65,536 successive probes and washings, which would take an enormous amount of time.

Imperfect hybridization has led to difficulties in generating adequate sequence.

Sequence determination would be impossible in such an instance.

Furthermore, sequencing by hybridization also encounters problems when there are repeats in sequences that are one base less than the length of the probe.

The most common limitation of most of these techniques is a short read length.

Comparisons of the different techniques show that only the impractical exonuclease sequencing has the theoretical capability of long read lengths.

Although this method has potential in practice it has encountered several problems and has not been demonstrated to be an effective method.

Each of the known methods for sequencing polymers has drawbacks.

For instance most of the methods are slow and labor intensive.

Methods such as mass spectroscopy and ELIDA sequencing can only be performed on very short polymers.

The rate of sequencing has limited the capability to generate multiple body and temporal expression maps which would undoubtedly aid the rapid determination of complex genetic function.

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