About this Research Topic
A 648bp segment of the mitochondrial cytochrome oxidase I gene, known as a “DNA barcode” has proven useful for species identification throughout the animal kingdom. Despite their practical utility, there are controversies concerning the uses and interpretation of DNA barcodes. Disagreement is normal in cutting-edge science, and interactive discourse should be encouraged rather than avoided. This Research Topic encourages such discourse in an effort to hopefully resolve some of the disagreements about DNA barcodes. The disagreements are on two distinct levels.
One level of disagreement is whether mtCOI DNA barcodes can legitimately be used for anything other than species identification. A second and separate level of disagreement goes on among workers who already agree with the premise that DNA barcodes can support population biology and evolutionary theory. The second argument concerns differing interpretations of what kingdom-wide similarities in the patterns of DNA barcodes mean.
Participants in each of these two controversies ought to listen to each other. Those who doubt the possibility that DNA barcodes can support deep interpretation ought to consider what comes out of considering them. A new approach should be judged by the results of using it. On the contrary, those who advocate different interpretations of DNA barcodes must consider the argument that DNA barcodes can never support deeper interpretation and their attempts are doomed at the start.
Different approaches are used to discriminate among species of protists, fungi, plants and members of the domains of Eubacteria and Archaea, thus raising the issue as to whether there is a single barcode approach that can be used across all forms of organisms. One might argue that in this age of sequencing “too cheap to meter”, DNA barcodes are a relic that should no longer be used.
In this Research Topic, we want to solicit research articles, reviews, and commentaries that provide critiques of DNA barcodes. Below is a non-inclusive list of topics that we feel are relevant to a thorough discussion of pros, cons and the further potential of DNA barcodes.
1. Are DNA barcodes useful beyond species identification?
2. Can short segments of DNA provide a means of valid phylogenetic comparisons among species? Do such sequences provide meaningful information about the overall level of genetic variation within a species?
3. Why do the mitochondrial sequences work so well in the kingdom Animalia - ~90% agreement with what domain experts call species - and why is this agreement quantitatively similar for mammals, fish, insects and birds?
4. What molecular and evolutionary mechanisms account for the similar variance found in DNA barcodes for species across the animal kingdom?
5. How can one objectively identify an appropriate barcode for a new and diverse group of organisms? Is there a general approach or algorithm that has been successful and might be repeated or systematically modified?
Keywords: Mitochondria, Speciation, Mechanisms, Nuclear-cytoplasmic compatibility, Neutral evolution