With 100% of the human genome mapped, new genetic diagnostic and disease screening tests may soon be available for clinical laboratories and pathology groups
Utilizing technology developed by two different biotechnology/genetic sequencing companies, an international consortium of genetic scientists claim to have sequenced 100% of the entire human genome, “including the missing parts,” STAT reported. This will give clinical laboratories access to the complete 3.055 billion base pair (bp) sequence of the human genome.
If validated, this achievement could greatly impact future genetic research and genetic diagnostics development. That also will be true for precision medicine and disease-screening testing.
Completing the First “End-to-End” Genetic Sequencing
In June of 2000, the Human Genome Project (HGP) announced it had successfully created the first “working draft” of the human genome. But according to the National Human Genome Research Institute (NHGRI), the draft did not include 100% of the human genome. It “consists of overlapping fragments covering 97% of the human genome, of which sequence has already been assembled for approximately 85% of the genome,” an NHGRI press release noted.
“The original genome papers were carefully worded because they did not sequence every DNA molecule from one end to the other,” Ewan Birney, PhD, Deputy Director General of the European Molecular Biology Laboratory (EMBL) and Director of EMBL’s European Bioinformatics Institute (EMBL-EBI), told STAT. “What this group has done is show that they can do it end-to-end. That’s important for future research because it shows what is possible,” he added.
In their published paper, the T2T scientists wrote, “Addressing this remaining 8% of the genome, the Telomere-to-Telomere (T2T) Consortium has finished the first truly complete 3.055 billion base pair (bp) sequence of a human genome, representing the largest improvement to the human reference genome since its initial release.”
Tale of Two Genetic Sequencing Technologies
Humans have a total of 46 chromosomes in 23 pairs that represent tens of thousands of individual genes. Each individual gene consists of numbers of base pairs and there are billions of these base pairs within the human genome. In 2000, scientists estimated that humans have only 30,000 to 35,000 genes, but that number has since been reduced to just above 20,000 genes.
According to STAT, “The work was possible because the Oxford Nanopore and PacBio technologies do not cut the DNA up into tiny puzzle pieces.”
PacBio used HiFi sequencing, which is only a few years old and provides the benefits of both short and long reads. STAT noted that PacBio’s technology “uses lasers to examine the same sequence of DNA again and again, creating a readout that can be highly accurate.” According to the company’s website, “HiFi reads are produced by calling consensus from subreads generated by multiple passes of the enzyme around a circularized template. This results in a HiFi read that is both long and accurate.”
Oxford Nanopore uses electrical current in its sequencing devices. In this technology, strands of base pairs are pressed through a microscopic nanopore one molecule at a time. Those molecules are then zapped with electrical currents to enable scientists to determine what type of molecule they are and, in turn, identify the full strand.
The T2T Consortium acknowledge in their paper that they had trouble with approximately 0.3% of the genome, but that, though there may be a few errors, there are no gaps.
“You’re just trying to dig into this final unknown of the human genome,” Karen Miga (above), Assistant Professor in the Biomolecular Engineering Department at the University of California, Santa Cruz (UCSC), Associate Director at the UCSC Genomics Institute, and lead author of the T2T Consortium study, told STAT. “It’s just never been done before and the reason it hasn’t been done before is because it’s hard.” (Photo copyright: University of California, Santa Cruz.)
Might New Precision Medicine Therapies Come from T2T Consortium’s Research?
The researchers claim in their paper that the number of known base pairs has grown from 2.92 billion to 3.05 billion and that the number of known genes has increased by 0.4%. Through their research, they also discovered 115 new genes that code for proteins.
The T2T Consortium scientists also noted that the genome they sequenced for their research did not come from a person but rather from a hydatidiform mole, a rare growth that occasionally forms on the inside of a women’s uterus. The hydatidiform occurs when a sperm fertilizes an egg that has no nucleus. As a result, the cells examined for the T2T study contained only 23 chromosomes instead of the full 46 found in most humans.
Although the T2T Consortium’s work is a huge leap forward in the study of the human genome, more research is needed. The consortium plans to publish its findings in a peer-reviewed medical journal. In addition, both PacBio and Oxford Nanopore plan to develop a way to sequence the entire 46 chromosome human genome in the future.
The future of genetic research and gene sequencing is to create technologies that will allow researchers to identify single nucleotide polymorphisms (SNPs) that contain longer strings of DNA. Because these SNPs in the human genome correlate with medical conditions and response to specific genetic therapies, advancing knowledge of the genome can ultimately provide beneficial insights that may lead to new genetic tests for medical diagnoses and help medical professionals determine the best, personalized therapies for individual patients.
Experts list the top challenges facing widespread adoption of proteomics in the medical laboratory industry
Year-by-year, clinical
laboratories find new ways to use mass spectrometry to
analyze clinical specimens, producing results that may be more precise than
test results produced by other methodologies. This is particularly true in the
field of proteomics.
However, though mass spectrometry is highly accurate and
fast, taking only minutes to convert a specimen into a result, it is not fully
automated and requires skilled technologists to operate the instruments.
Thus, although the science of proteomics is advancing
quickly, the average pathology laboratory isn’t likely to be using mass
spectrometry tools any time soon. Nevertheless, medical
laboratory scientists are keenly interested in adapting mass spectrometry
to medical lab test technology for a growing number of assays.
Molly Campbell, Science Writer and Editor in Genomics, Proteomics, Metabolomics, and Biopharma at Technology Networks, asked proteomics experts “what, in their opinion, are the greatest challenges currently existing in proteomics, and how can we look to overcome them?” Here’s a synopsis of their answers:
Lack of High Throughput Impacts Commercialization
Proteomics isn’t as efficient as it needs to be to be
adopted at the commercial level. It’s not as efficient as its cousin genomics. For it to become
sufficiently efficient, manufacturers must be involved.
John Yates
III, PhD, Professor, Department of Molecular Medicine at Scripps Research California
campus, told Technology
Networks, “One of the complaints from funding agencies is that you can
sequence literally thousands of genomes very quickly, but you can’t do the same
in proteomics. There’s a push to try to increase the throughput of proteomics
so that we are more compatible with genomics.”
For that to happen, Yates says manufacturers need to
continue advancing the technology. Much of the research is happening at
universities and in the academic realm. But with commercialization comes
standardization and quality control.
“It’s always exciting when you go to ASMS [the conference for the American Society
for Mass Spectrometry] to see what instruments or technologies are going to be
introduced by manufacturers,” Yates said.
There are signs that commercialization isn’t far off. SomaLogic, a privately-owned American protein
biomarker discovery and clinical diagnostics company located in Boulder, Colo.,
has reached the commercialization stage for a proteomics assay platform called SomaScan. “We’ll be
able to supplant, in some cases, expensive diagnostic modalities simply from a
blood test,” Roy
Smythe, MD, CEO of SomaLogic, told Techonomy.
The graphic above illustrates the progression mass spectrometry took during its development, starting with small proteins (left) to supramolecular complexes of intact virus particles (center) and bacteriophages (right). Because of these developments, today’s medical laboratories have more assays that utilize mass spectrometry. (Photo copyright: Technology Networks/Heck laboratory, Utrecht University, the Netherlands.)
Achieving the Necessary Technical Skillset
One of the main reasons mass spectrometry is not more widely
used is that it requires technical skill that not many professionals possess.
“For a long time, MS-based proteomic analyses were technically demanding at
various levels, including sample processing, separation science, MS and the
analysis of the spectra with respect to sequence, abundance and
modification-states of peptides and proteins and false discovery rate
(FDR) considerations,” Ruedi
Aebersold, PhD, Professor of Systems Biology at the Institute of Molecular Systems Biology (IMSB) at
ETH Zurich, told Technology
Networks.
Aebersold goes on to say that he thinks this specific
challenge is nearing resolution. He says that, by removing the problem created
by the need for technical skill, those who study proteomics will be able to
“more strongly focus on creating interesting new biological or clinical
research questions and experimental design.”
Yates agrees. In a paper titled, “Recent Technical Advances in
Proteomics,” published in F1000 Research, a peer-reviewed open research
publishing platform for scientists, scholars, and clinicians, he wrote, “Mass
spectrometry is one of the key technologies of proteomics, and over the last
decade important technical advances in mass spectrometry have driven an
increased capability of proteomic discovery. In addition, new methods to
capture important biological information have been developed to take advantage
of improving proteomic tools.”
No High-Profile Projects to Stimulate Interest
Genomics had the Human Genome Project
(HGP), which sparked public interest and attracted significant funding. One of
the big challenges facing proteomics is that there are no similarly big,
imagination-stimulating projects. The work is important and will result in
advances that will be well-received, however, the field itself is complex and difficult
to explain.
Emanuel
Petricoin, PhD, is a professor and co-director of the Center for Applied
Proteomics and Molecular Medicine at George
Mason University. He told Technology
Networks, “the field itself hasn’t yet identified or grabbed onto a
specific ‘moon-shot’ project. For example, there will be no equivalent to the
human genome project, the proteomics field just doesn’t have that.”
He added, “The equipment needs to be in the background and
what you are doing with it needs to be in the foreground, as is what happened
in the genomics space. If it’s just about the machinery, then proteomics will
always be a ‘poor step-child’ to genomics.”
Democratizing Proteomics
Alexander
Makarov, PhD, is Director of Research in Life Sciences Mass Spectrometry
(MS) at Thermo Fisher
Scientific. He told Technology
Networks that as mass spectrometry grew into the industry we have today,
“each new development required larger and larger research and development teams
to match the increasing complexity of instruments and the skyrocketing
importance of software at all levels, from firmware to application. All this
extends the cycle time of each innovation and also forces [researchers] to
concentrate on solutions that address the most pressing needs of the scientific
community.”
Makarov describes this change as “the increasing democratization of MS,” and says that it “brings with it new requirements for instruments, such as far greater robustness and ease-of-use, which need to be balanced against some aspects of performance.”
One example of the increasing democratization of MS may be
several public proteomic datasets available to scientists. In European
Pharmaceutical Review, Juan
Antonio Viscaíno, PhD, Proteomics Team Leader at the European Bioinformatics Institute (EMBL-EBI)
wrote, “These datasets are increasingly reused for multiple applications, which
contribute to improving our understanding of cell biology through proteomics
data.”
Sparse Data and Difficulty Measuring It
Evangelia
Petsalaki, PhD, Group Leader EMBL-EBI, told Technology
Networks there are two related challenges in handling proteomic data.
First, the data is “very sparse” and second “[researchers] have trouble
measuring low abundance proteins.”
Petsalaki notes, “every time we take a measurement, we
sample different parts of the proteome or phosphoproteome and
we are usually missing low abundance players that are often the most important
ones, such as transcription
factors.” She added that in her group they take steps to mitigate those
problems.
“However, with the advances in MS technologies developed by
many companies and groups around the world … and other emerging technologies
that promise to allow ‘sequencing’ proteomes, analogous to genomes … I expect
that these will not be issues for very long.”
So, what does all this mean for clinical laboratories? At the
current pace of development, its likely assays based on proteomics could become
more common in the near future. And, if throughput and commercialization ever
match that of genomics, mass spectrometry and other proteomics tools could
become a standard technology for pathology laboratories.
