The draft genome of horseshoe crab Tachypleus tridentatus reveals its evolutionary scenario and well-developed innate immunity
Background: Horseshoe crabs are ancient marine arthropods with a long evolutionary history extending back approximately 450 million years, which may benefit from their innate immune systems. However, the genetic mechanisms underlying their abilities of distinguishing and defending against invading microbes are still unclear. Results: Here, we describe the 2.06 Gbp genome assembly of Tachypleus tridentatus with 24,222 predicted protein-coding genes. Comparative genomics shows that T. tridentatus and the Atlantic horseshoe crab Limulus polyphemus have the most orthologues shared among two species, including genes involved in the immune-related JAK-STAT signalling pathway. Divergence time dating results show that the last common ancestor of Asian horseshoe crabs (including T. tridentatus and C. rotundicauda ) and L. polyphemus appeared approximately 130 Mya (121-141), and the split of the two Asian horseshoe crabs was dated to approximately 63 Mya (57-69). Hox gene analysis suggests two clusters in both horseshoe crab assemblies. Surprisingly, selective analysis of immune-related gene families revealed the high expansion of conserved pattern recognition receptors. Genes involved in the IMD and JAK-STAT signal transduction pathways also exhibited a certain degree of expansion in both genomes. Intact coagulation cascade-related genes were present in the T. tridentatus genome with a higher number of coagulation factor genes. Moreover, most reported antibacterial peptides have been identified in T. tridentatus with their potentially effective antimicrobial sites. Conclusions: The draft genome of T. tridentatus would would provide important evidence for further clarifying the taxonomy and evolutionary relationship of Chelicerata. The expansion of conserved immune signalling pathway genes, coagulation factors and intact antimicrobial peptides in T. tridentatus constitutes its robust and effective innate immunity for self-defence in marine environments with an enormous number of invading pathogens and may affect the quality of the adaptive properties with regard to complicated marine environments.
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The draft genome of horseshoe crab Tachypleus tridentatus reveals its evolutionary scenario and well-developed innate immunity
Posted 14 Jan, 2020
On 10 Feb, 2020
On 13 Jan, 2020
On 13 Jan, 2020
On 12 Jan, 2020
On 12 Jan, 2020
On 08 Jan, 2020
On 08 Jan, 2020
On 03 Jan, 2020
On 27 Dec, 2019
On 26 Dec, 2019
On 26 Dec, 2019
On 17 Dec, 2019
Received 05 Dec, 2019
Received 05 Dec, 2019
Invitations sent on 20 Nov, 2019
On 20 Nov, 2019
On 20 Nov, 2019
On 12 Nov, 2019
On 11 Nov, 2019
On 11 Nov, 2019
On 20 Oct, 2019
Received 17 Oct, 2019
Received 11 Sep, 2019
On 25 Aug, 2019
Invitations sent on 25 Aug, 2019
On 25 Aug, 2019
On 12 Aug, 2019
On 11 Aug, 2019
On 11 Aug, 2019
On 22 Jun, 2019
Received 16 Jun, 2019
Received 14 Jun, 2019
On 27 May, 2019
On 25 May, 2019
Invitations sent on 07 May, 2019
On 30 Apr, 2019
On 30 Apr, 2019
On 30 Apr, 2019
On 21 Apr, 2019
Background: Horseshoe crabs are ancient marine arthropods with a long evolutionary history extending back approximately 450 million years, which may benefit from their innate immune systems. However, the genetic mechanisms underlying their abilities of distinguishing and defending against invading microbes are still unclear. Results: Here, we describe the 2.06 Gbp genome assembly of Tachypleus tridentatus with 24,222 predicted protein-coding genes. Comparative genomics shows that T. tridentatus and the Atlantic horseshoe crab Limulus polyphemus have the most orthologues shared among two species, including genes involved in the immune-related JAK-STAT signalling pathway. Divergence time dating results show that the last common ancestor of Asian horseshoe crabs (including T. tridentatus and C. rotundicauda ) and L. polyphemus appeared approximately 130 Mya (121-141), and the split of the two Asian horseshoe crabs was dated to approximately 63 Mya (57-69). Hox gene analysis suggests two clusters in both horseshoe crab assemblies. Surprisingly, selective analysis of immune-related gene families revealed the high expansion of conserved pattern recognition receptors. Genes involved in the IMD and JAK-STAT signal transduction pathways also exhibited a certain degree of expansion in both genomes. Intact coagulation cascade-related genes were present in the T. tridentatus genome with a higher number of coagulation factor genes. Moreover, most reported antibacterial peptides have been identified in T. tridentatus with their potentially effective antimicrobial sites. Conclusions: The draft genome of T. tridentatus would would provide important evidence for further clarifying the taxonomy and evolutionary relationship of Chelicerata. The expansion of conserved immune signalling pathway genes, coagulation factors and intact antimicrobial peptides in T. tridentatus constitutes its robust and effective innate immunity for self-defence in marine environments with an enormous number of invading pathogens and may affect the quality of the adaptive properties with regard to complicated marine environments.
Figure 1
Figure 2
Figure 3
Figure 4