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The Revolution in Molecular Phylogenetics: From Chemical Classification to the Evolution of DNA Sequence
With the advancement of science and technology, the rise of molecular systematics has changed the way we understand biological diversity. Molecular systematics provides important information about the evolutionary relationships of organisms by analyzing differences in gene sequences. This allows scientists to construct a tree of life that depicts how species are related, all based on decades of scientific research.
Molecular systematics is a broad term for the use of molecular data in taxonomy and biogeography,
The theoretical framework of molecular systematics can be traced back to the 1960s. At that time, scientists such as Emile Zuckerkandl, Emanuel Margoliash and Linus Pauling laid the foundation of gamma classics. Although imperfect, these early studies had begun to question long-held ideas about biological classification. For example, the systematic classification of birds was revised based on molecular evidence.
In the 1970s and 1980s, DNA-DNA hybridization became a mainstream technique for measuring genetic differences. This made it possible to shift traditional morphological classification to molecular analysis, paving the way for subsequent molecular evolutionary studies. Now, by sequencing specific gene segments, researchers can delve deeper into the genetic relationships between species.
Early molecular systematics methods were called chemical classification and used proteins, enzymes, carbohydrates, etc. as research objects.
As technology advances, DNA sequencing technology has developed rapidly and is now able to provide more accurate genetic sequence analysis than ever before. These techniques allow researchers to sequence data that is much more detailed, typically covering about 1,000 base pairs, and can be used to determine haplotypes for each species. Although completely sequencing an organism's genome remains a challenge, analyzes targeting specific chromosomal regions have become feasible.
Today's molecular phylogenetic analysis usually follows a rigorous approach, which includes steps such as sequence acquisition, multiple sequence alignment, model testing, and evolutionary tree reconstruction. Each of these procedures must be carefully designed to ensure reliable results. The popularization of high-throughput sequencing technology has also provided strong support for genomics and transcriptomics research.
In molecular evolution, the structures of DNA, RNA and proteins in living organisms show an interesting similarity.
In terms of application, the promotion of DNA barcoding technology allows us to quickly identify species, and in the field of forensic science, genetic fingerprinting technology has also helped solve many cases. As molecular systematics continues to advance, our understanding of evolution among species is getting better and better over time.
At the same time, however, molecular systematics also faces challenges, such as the discovery of horizontal gene transfer, which has complicated phylogenetic effects. This means that different genes in the same organism may have different evolutionary paths, which poses a certain challenge to the establishment of dendrograms. In this context, scientists need to adopt more flexible analysis methods to promote accurate classification and system construction.
Many modern tree construction methods rely on multiple sequence alignments to enhance the reliability of the results.
It is worth noting that dendrogram analysis based on different models may lead to different results, so choosing the right model is crucial. In short, molecular systematics is constantly evolving, and with technological innovation, its applications are becoming more widespread, affecting everything from biology to medicine.
As we trace the evolution of species, we have to ask: As our knowledge continues to grow, how will future scientific research continue to change our understanding of life?
