Genetic Diversity at Toll Like Receptor 7 (TLR7) Gene of Sri Lankan Indigenous Chicken and Ceylon Jungle Fowl (&lt;i&gt;Gallus lafayetti&lt;/i&gt;)

Bulumulla, P. B. A. I. K.; Silva, P.; Han, Jin‐Hee

doi:10.4038/tar.v22i4.3787

Cited by 5 publications

(3 citation statements)

References 9 publications

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“…This discrepancy could be consistent with a relaxed selection acting at this locus, reflecting the high diversity of intra-cellular pathogens that could possibly be encountered in the environment (39,41). To our knowledge, the diversity of TLR-7 has not been described in bivalves, and a high level of TLR-7 has just been observed in chicken (80,81). Conversely, the two other types of vesicular TLRs (i.e., TLR-13 and TLR-3) sense more structurally conserved double-stranded bacterial RNAs.…”

Section: Variation Of Tlr Genesmentioning

confidence: 59%

The characterization of toll-like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression.

Coupé

Prévot

Giantsis

et al. 2022

Preprint

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The fan mussel Pinna nobilis is currently on the brink of extinction due to a multifactorial disease mainly caused to the highly pathogenic parasite Haplosporidium pinnae, meaning that the selection pressure outweighs the adaptive potential of the species. Hopefully, rare specimens have been observed somehow resistant to the parasite, stretching the need to identify the traits underlying this better fitness. Among the candidate to explore at first intention are fast evolving immune genes, of which toll-like receptor (TLR). In this study, we examined the genetic diversity at 14 TLR loci across Pinna nobilis, Pinna rudis and Pinna nobilis x Pinna rudis hybrid genomes, collected at four physically distant regions, that were found to be either resistant or sensitive to the parasite Haplosporidium pinnae. We report a high genetic diversity, mainly observed at cell surface TLRs compared to that of endosomal TLRs. However, the TLR-7 and TLR-1 exhibited unexpected level of diversity and haplotype phylogeny, respectively. The lack of population structure, associated with a high genetic diversity and elevated dN/dS ratio were interpreted as balancing selection, though both directional and purifying selection were detected. Overall, we observed small contributions of putatively selected SNPs involved in the resistance. However, the most contributing SNPs were carried by two TLR-6 loci and might be used as potent biomarkers of distinguish between resistant and sensitive P. nobilis individuals. Moreover, more than 10% of P. nobilis individuals were found introgressed with P. rudis. Noteworthy, all introgressed P. nobilis observed as resistant to H. pinnae carried a TLR-7 of P. rudis origin. This study contributes to the ongoing efforts towards conservation carried out to prevent from extinction this Mediterranean endemic species.

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Section: Variation Of Tlr Genesmentioning

confidence: 59%

The characterization of toll-like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression.

Coupé

Prévot

Giantsis

et al. 2022

Preprint

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“…Such a contribution of recombination has already been evidenced in immune genes, including TLR (Gösser et al, 2019; Oren et al, 2019; Schaschl et al, 2006). To our knowledge, the diversity of TLR‐7 has not been described in bivalves, and a high level of TLR‐7 has just been observed in chicken (Bulumulla et al, 2011; Świderská et al, 2018). Conversely, the two other types of vesicular TLRs (i.e.…”

Section: Discussionmentioning

confidence: 93%

The characterization of toll‐like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression

Coupé

Giantsis

Vázquez‐Luis

et al. 2023

Ecology and Evolution

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The fan mussel Pinna nobilis is currently on the brink of extinction due to a multifactorial disease mainly caused to the highly pathogenic parasite Haplosporidium pinnae, meaning that the selection pressure outweighs the adaptive potential of the species. Hopefully, rare individuals have been observed somehow resistant to the parasite, stretching the need to identify the traits underlying this better fitness. Among the candidate to explore at first intention are fast‐evolving immune genes, of which toll‐like receptor (TLR). In this study, we examined the genetic diversity at 14 TLR loci across P. nobilis, Pinna rudis and P. nobilis × P. rudis hybrid genomes, collected at four physically distant regions, that were found to be either resistant or sensitive to the parasite H. pinnae. We report a high genetic diversity, mainly observed at cell surface TLRs compared with that of endosomal TLRs. However, the endosomal TLR‐7 exhibited unexpected level of diversity and haplotype phylogeny. The lack of population structure, associated with a high genetic diversity and elevated dN/dS ratio, was interpreted as balancing selection, though both directional and purifying selection were detected. Interestingly, roughly 40% of the P. nobilis identified as resistant to H. pinnae were introgressed with P. rudis TLR. Specifically, they all carried a TLR‐7 of P. rudis origin, whereas sensitive P. nobilis were not introgressed, at least at TLR loci. Small contributions of TLR‐6 and TLR‐4 single‐nucleotide polymorphisms to the clustering of resistant and susceptible individuals could be detected, but their specific role in resistance remains highly speculative. This study provides new information on the diversity of TLR genes within the P. nobilis species after MME and additional insights into adaptation to H. pinnae that should contribute to the conservation of this Mediterranean endemic species.

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“…Toll like receptor 7 (TLR7) nowadays relies on molecular genetic tools. A study used a total of 24 SNPs and 35 haplotypes within the family of Toll Like Receptors genes to investigate genetic variability in immune response traits of Sri Lankan Indigenous chickens [47]. An investigation of the polymorphism at a single Mx locus inferred on resistance of populations to Avian Influenza [48].…”

Section: Previous Attempts To Characterize and Manipulate Adaptive Gementioning

confidence: 99%

Genomics Tools for the Characterization of Genetic Adaptation of Low Input Extensively Raised Chickens

Muchadeyi¹,

Dzomba²

2017

Poultry Science

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Evolutionary change emanating from diferential contribution of genotypes to the next generation can determine success in survival and reproduction in chickens. For extensively raised chickens reared under low-input production systems in smallholder farming areas, conditions of resources deprivation and exposure to diverse and threatening natural selection pressures are common in many countries worldwide. Numerous studies have demonstrated that village chickens and other extensively raised chicken populations represent a valuable source of biodiversity adapted to the local production conditions and selection pressures. Manipulation of their acquired adaptive genetic diversity depends on unravelling the selection footprints in the genomes of these chickens that could point towards candidate genes for traits that enable the animals to survive under the harsh production environments. This chapter summarizes the evidence for chickens adaptation to extreme environments and describes an inventory of modern tools that could be used in characterizing the production systems of chicken genetic resources. The role of natural selection in shaping the biodiversity of chicken genetic resources is discussed. The continued advancement of biotechnological tools to assess chicken populations has been beneicial to research in genetic adaptation. Genomics tools, as evidenced by assays of whole genome and transcriptome sequences, and single nucleotide polymorphism SNP) genotypes of chickens, now allow analyses of functional genomic regions that are linked to adaptation. The use of these methods to characterize and investigate signatures of selection in the chicken genomes is highlighted. This chapter looks at how information on the selection hotspots in the chicken genomes can be manipulated to improve genetic adaptation in indigenous chicken populations with the desire to transfer the beneits to other chicken breeds raised under similar production systems.

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Genetic Diversity at Toll Like Receptor 7 (TLR7) Gene of Sri Lankan Indigenous Chicken and Ceylon Jungle Fowl (<i>Gallus lafayetti</i>)

Cited by 5 publications

References 9 publications

The characterization of toll-like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression.

The characterization of toll-like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression.

The characterization of toll‐like receptor repertoire in Pinna nobilis after mass mortality events suggests adaptive introgression

Genomics Tools for the Characterization of Genetic Adaptation of Low Input Extensively Raised Chickens

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