As we will see, you can be scared of anything if you are ignorant and/or seeking to mislead and smear.
Reverse genetics is a research technique for identifying the function of genes by looking for traits that arise when a gene of interest is artificially modified, not a technique for genetic modification and of itself.It is called that in contrast to forward genetics, which is the traditional technique for identifying the genes responsible for a particular existing trait. Reverse genetics creates traits
In the context of the vaccine synthesis portion of the Wikipedia article you linked, reverse genetics is used by making modifications to viral genes and looking to see if it induces traits that reduce pathogenicity and increase immune response.
Now for the meat.
After looking through the Senate report, I found the reference to “undetectable” genetic modifications. As expected, it is an example of scientifically uninformed individuals making incorrect and disingenuous conclusions. The Senate report, on page 39, singles out a quote from the 2005 paper “Development of Mouse Hepatitis Virus and SARS-CoV Infectious cDNA Constructs” (Development of Mouse Hepatitis Virus and SARS-CoV Infectious cDNA Constructs | SpringerLink).
This is the paragraph the quote comes from:
Molecularly cloned viruses were indistinguishable from wild type and contained the marker mutations and unique BglI and BstXI junction sequences used in the assembly of the infectious construct (Yount et al. 2000)
However, this quote does not refer to work done by Baric in 2005 but work done in 2000 (Strategy for Systematic Assembly of Large RNA and DNA Genomes: Transmissible Gastroenteritis Virus Model | Journal of Virology) and refers to phenotypic qualities, not genetic qualities. The relevant quote is
These data indicate that viruses derived from the infectious cDNA construct had phenotypes indistinguishable from those of wild-type TGEV in swine cells.
In other words, the synthetic viruses these quotes refer to have the same biological function, not identical genetics. In fact, the latter portion of the misused quote, “marker mutations and unique BglI and BstXI junction sequences used in the assembly of the infectious construct”, refer to identifiable markers of genetic modification. The singled out quote in the Senate report is wholly misconstrued and arguably an outright lie.
Similarly, subsequent references to “no-see-um” techniques are actually the author’s method of cloning smaller genetic fragments without leaving what are known as “scars” from the assembly of restriction enzyme-based cloning. Such a goal, regardless of method, is required when trying to assemble functional coding sequences without disrupting the original function from the addition of restriction sites. It is not an overarching technique for so-called “undetectable” genetic modification. They were undoubtedly influenced by the connotations of the phrase itself and, lacking requisite knowledge of genetic engineering to interpret these papers, simply ran with it.
Additionally, all of these techniques are a product of the comparatively immature state of DNA and RNA synthesis in the early 2000s. Modern synthesis techniques are able to synthesize much, much longer DNA fragments on demand without the need for the types of manipulation, side artifacts, and cloning methods described above. It would be possible to synthetically generate an edited portion of DNA without the kind of “cut and paste” techniques required in the past. This is not the product of some kind of shadowy conspiracy or malicious technology but simply the general state of synthetic biology available today. Even with an entirely synthetic genome, any genetic changes would be evident when compared to the genome of a wild-type sample.
The Senate report is ultimately a disingenuous scare piece taking misunderstood and out-of-context work to claim that because supposedly “undetectable” genetic engineering was used in research 15 years ago it must be the case SARS-CoV-2 is also such a product along with implying Baric and his colleagues are part of the conspiracy.