Comparative genomics reveals adaptive evolution of Asian tapeworm in switching to a new intermediate host

Abstract

Taenia saginata, Taenia solium and Taenia asiatica (beef, pork and Asian tapeworms, respectively) are parasitic flatworms of major public health and food safety importance. Among them, T. asiatica is a newly recognized species that split from T. saginata via an intermediate host switch ∼1.14 Myr ago. Here we report the 169- and 168-Mb draft genomes of T. saginata and T. asiatica. Comparative analysis reveals that high rates of gene duplications and functional diversifications might have partially driven the divergence between T. asiatica and T. saginata. We observe accelerated evolutionary rates, adaptive evolutions in homeostasis regulation, tegument maintenance and lipid uptakes, and differential/specialized gene family expansions in T. asiatica that may favour its hepatotropism in the new intermediate host. We also identify potential targets for developing diagnostic or intervention tools against human tapeworms. These data provide new insights into the evolution of Taenia parasites, particularly the recent speciation of T. asiatica.

Gene Duplication Analysis Reveals No Ancient Whole Genome Duplication but Extensive Small-Scale Duplications during Genome Evolution and Adaptation of Schistosoma mansoni

“…However, the present analysis based on the L-shaped Ks age distribution revealed that paleopolyploidies are probably absent in the fluke lineage in a relatively long evolutionary time (Ks ≤ 5) (Figure 1 ). It is consistent with the case of the investigation of paralogous genes in tapeworms that no sudden peak was observed in Ks age distributions (Wang et al, 2016 ). This estimation is further confirmed by the result from the collinearity block analysis that no genomic region with more than 5 genes was successfully called by MCScanX algorithm, indicative of absence of large segmental duplications.…”

“…In addition, some duplicated genes have been demonstrated to play central roles in adaptations to some specific niches, such as, Dca gene that is involved in adaptation to lower temperature in Drosophila (Arboleda-Bustos and Segarra, 2011 ), and major histocompatibility complex (Burri et al, 2010 ) and immunoglobulin gene families (Guldner et al, 2004 ) that are likely linked to host-pathogen interactions. For an evolutionarily specialized group, parasites have undergone long-term adaptations and evolved a lot of specialized mechanisms to interact with their hosts during life cycles (Tsai et al, 2013 ; Jackson, 2015 ; Zarowiecki and Berriman, 2015 ; Wang et al, 2016 ). Therefore, it will be particularly important to investigate the nature and extent of GD in genomes of parasites to better understand the associations between GD events and evolutionary adaptations.…”

Fall webworm genomes yield insights into rapid adaptation of invasive species

“…Novel genes and duplications are thought to be primary forces in species-specific adaptation and divergence by allowing the differentiation of gene functions 10,11 . Thus, they may provide insights into the understanding of fall webworm-specific attributes.…”

Fasciclin-calcareous corpuscle binary complex mediated protein-protein interactions in Taenia solium metacestode

“…Arbitrarily, proteins were selected from each taxon by considering identity and expected values. Two orthologous proteins that found in Taenia saginata by blast search in WormBase ParaSite ( http://parasite.wormbase.org/Multi/Tools/Blast?db=core ) were also included [ 27 ]. Amino acid sequences of selected proteins were aligned with ClustalW and applied in a phylogenetic analysis using the maximum-likelihood algorithm of Mega 6.0 ( http://www.megasoftware.net/ ) (Jones-Thornton-Tayler model for amino acid substitution, rate heterogeneity with 4 gamma category).…”