Phylogenetics
Microbial Phylogenetics: Horizontal Gene Transfer
Efforts to construct the tree of life take their conceptual motivation from Charles Darwin's theory of evolution. Until the advent of molecular biology, however, a universal tree of life was well beyond the scope of the data and methods of traditional organismal phylogeny. The rapid development of these methods and bodies of genetic sequence from the 1970s onwards resulted in major reclassifications of life and revived ambitions to represent all organismal lineages by one true tree of life. Subsequent realization of the significance of lateral gene transfer and other non-vertical processes has subtly reconceptualized and reoriented attempts to construct this universal phylogeny.
Gene transfer has affected the formation of groups of organisms. Gene transfer can make it more difficult to define and determine relationships. In those cases where many genes have been transferred between preferred partners, the majority of genes in a genome may reflect gene acquisition, and as a consequence, if a coherent signal is detected, one nevertheless might not be sure that the signal is due to organismal shared ancestry. However, the presence of a particular transferred gene has been shown, in several cases, to constitute a shared derived character useful in classification. Gene transfer can put together new metabolic pathways that open up new ecological niches, and consequently, the transfer of an adaptive gene might create a new group of organisms read more ...
from Molecular Phylogeny of Microorganisms by Aharon Oren and R. Thane Papke (2010)
References
Gene transfer has affected the formation of groups of organisms. Gene transfer can make it more difficult to define and determine relationships. In those cases where many genes have been transferred between preferred partners, the majority of genes in a genome may reflect gene acquisition, and as a consequence, if a coherent signal is detected, one nevertheless might not be sure that the signal is due to organismal shared ancestry. However, the presence of a particular transferred gene has been shown, in several cases, to constitute a shared derived character useful in classification. Gene transfer can put together new metabolic pathways that open up new ecological niches, and consequently, the transfer of an adaptive gene might create a new group of organisms read more ...
from Molecular Phylogeny of Microorganisms by Aharon Oren and R. Thane Papke (2010)
References
Evolution of Plastids
Photosynthesis is one of the most successful energy production strategies on the planet and has been co-opted numerous times throughout evolutionary history via the uptake and retention of photosynthetic cells by non-photosynthetic eukaryotic heterotrophs. Whereas the result of this process is clear, what is not settled is the mode and tempo of plastid movement among eukaryotes, particularly plastids of red algal derivation. Recent changes in our understanding of the relationships between eukaryotic supergroups have only served to complicate the picture further. Of particular interest is the evolution of plastids, the relationships among photosynthetic eukaryotes, the process of endosymbiogenesis and the variation in ways plastids have been modified to suit the light harvesting needs of their hosts. The understanding of all of these factors is an active field of continued research that will undoubtedly lead to further discoveries in the coming years read more ...
from Molecular Phylogeny of Microorganisms by Aharon Oren and R. Thane Papke (2010)
References
from Molecular Phylogeny of Microorganisms by Aharon Oren and R. Thane Papke (2010)
References