Horizontal genetic transfer was then described in Seattle inin a paper demonstrating that the transfer of a viral gene into Corynebacterium diphtheriae created a virulent strain from a non-virulent strain,  also simultaneously solving the riddle of diphtheria that patients could be infected with the bacteria but not have any symptoms, and then suddenly convert later or never and giving the first example for the relevance of the lysogenic cycle. As Jian, Rivera and Lake put it:
However, interactions between them are rarely studied. Phylogenetic analyses of purple bacterial carotenoid biosynthesis genes suggest two lineages: Of the latter lineage, Rubrivivax gelatinosus S1 and Hoeflea phototrophica DFL also or instead produce spheroidenone.
Evolution of the spheroidenone pathway from that producing spirilloxanthin theoretically requires changes in the substrate specificity of upstream pathway enzymes and acquisition of a terminal ketolase CrtA.
Estimation of nonsynonymous and synonymous mutations using several pairwise methods indicated positive selection upon both genes, consistent with their functional changes from hydroxylases to ketolases. Relaxed negative selection upon all other carotenoid biosynthetic genes in these organisms was also apparent, likely facilitating changes in their substrate specificities.
Furthermore, all genes responsible for terminal carotenoid biosynthetic pathway steps were under reduced negative selection compared to those known to govern biosynthetic pathway specificity.
Horizontal transfer of crtA into R. These results highlight the importance and complexity of selection acting upon both a horizontally transferred gene and the biochemical network into which it is integrating.
Biochemical pathway evolution has been examined extensively, particularly regarding mechanisms by which novel functions can be generated, diversified, and maintained 9 Best studied in this regard is the role of gene duplication followed by divergence, resulting in paralog families that, despite sharing a common evolutionary ancestor, possess different functions Horizontal gene transfer between distantly related organisms is especially diversifying due to the likelihood of altering the genome structure or biochemical and regulatory networks of the recipient, in contrast to recombination between close relatives, which may promote genetic cohesion Selection controls phenotypic diversity as a function of evolutionary fitness.
Three scenarios can be detected from patterns of nucleotide substitutions Considering horizontal transfer, selection will favor fixation of a horizontally transferred gene if its phenotype is advantageous and will disfavor it when either the gene product or the alterations that it causes in the host network are deleterious.
Successful horizontal gene transfer resulting in gene fixation is the result of net evolutionary benefit for the host, due both to the horizontally transferred gene itself and to minimal suboptimal alteration of the host metabolic and genetic networks into which it is integrating.
Genetic parasites such as plasmids, transposons, and integrated phages are exceptional in directly promoting their own retention.
Carotenoids are isoprenoid pigments produced by many bacteria and fungi and all photosynthetic eukaryotes 78.
They are typically colored red, orange, and yellow due to their extensively conjugated polyene chains 7. In all photosynthetic organisms, carotenoids facilitate the assembly of the photosynthetic reaction center and interact with it as auxiliary light-harvesting pigments and antioxidant molecules 13 - Indeed, the niche in which a particular phototroph lives is defined, at least in part, by the absorption spectrum of its pigments, including light-harvesting carotenoids Carotenoids also modulate membrane fluidity and permeability 19 ; these functions remain poorly understood.
In this study, the evolution of carotenoid biosynthesis by horizontal gene transfer and selection is evaluated in the purple bacteria, anoxygenic phototrophic Proteobacteria that can use reduced sulfur compounds as electron sources.
Whereas phylogenetically most purple bacteria belong to the Alphaproteobacteria, some belonging to the Betaproteobacteria and Gammaproteobacteria have evolved by horizontal transfer of alphaproteobacterial photosynthetic superoperons, which include carotenoid biosynthetic genes 24 Carotenoid biosynthesis in the purple bacteria Fig.
The phytoene desaturase CrtI then desaturates phytoene either three or four times, producing neurosporene or lycopene, respectively. Considerable subpathway diversity also exists because of the potential for asymmetry between carotenoid ends.Horizontal gene transfer and selection are major forces driving microbial evolution.
However, interactions between them are rarely studied. Phylogenetic analyses of purple bacterial carotenoid biosynthesis genes suggest two lineages: one producing spheroidenone and the other producing spirilloxanthin.
Such transfer preserved the gene arrangement observed in certain fungi, in which the entire region, encompassing divergently transcribed carotenoid desaturase and carotenoid synthase–carotenoid cyclase loci, comprises only about 5 kilobases (kb) (25, 26).
R. Acuña et al., “Adaptive horizontal transfer of a bacterial gene to an invasive insect pest of coffee,” PNAS, , P. Ioannidis et al., “Rapid transcriptome sequencing of an invasive pest, the brown marmorated stink bug Halyomorpha halys,” BMC Genomics, , Horizontal Gene Transfer Responsible for Carotenoid Production in Aphids Horizontal Gene Transfer Horizontal gene transfer (referred to as HGT for the rest of the paper) is said to have occurred when an organism successfully incorporates genetic information from another organism into its own genetic makeup when the first organism is not the offspring of the other organism.
Transcript of Carotenoid Gene Transfer from Fungi to Aphids. Carotenoid Gene base pair substitution of G to A cuasing amino acid substitution of glutamine to lysine tor locus responsible for the enzyme carotenoid desaturase which is involved in producing the red torulene pigment (AKA Horizontal Gene Transfer) DNA is NOT from parent to.
Apr 23, · Such a sequential transfer could involve organisms like Wolbachia bacteria, which are known to infect both animal groups [11,12] and which are involved in diverse horizontal gene transfer events in arthropods [13,14].