Abstract
The current paradigm of gut evolution assumes that non-bilaterian metazoan lineages either lack a gut (Porifera and Placozoa) or have a sac-like gut (Ctenophora and Cnidaria) and that a through-gut originated within Bilateria [1–8]. An important group for understanding early metazoan evolution is Ctenophora (comb jellies), which diverged very early from the animal stem lineage [9–13]. The perception that ctenophores possess a sac-like blind gut with only one major opening remains a commonly held misconception [4, 5, 7, 14, 15]. Despite descriptions of the ctenophore digestive system dating to Agassiz [16] that identify two openings of the digestive system opposite of the mouth—called “excretory pores” by Chun [17], referred to as an “anus” by Main [18], and coined “anal pores” by Hyman [19]—contradictory reports, particularly prominent in recent literature, posit that waste products are primarily expelled via the mouth [4, 5, 7, 14, 19–23]. Here we demonstrate that ctenophores possess a unidirectional, functionally tripartite through-gut and provide an updated interpretation for the evolution of the metazoan through-gut. Our results resolve lingering questions regarding the functional anatomy of the ctenophore gut and long-standing misconceptions about waste removal in ctenophores. Moreover, our results present an intriguing evolutionary quandary that stands in stark contrast to the current paradigm of gut evolution: either (1) the through-gut has its origins very early in the metazoan stem lineage or (2) the ctenophore lineage has converged on an arrangement of organs functionally similar to the bilaterian through-gut.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2814-2820 |
| Number of pages | 7 |
| Journal | Current Biology |
| Volume | 26 |
| Issue number | 20 |
| DOIs | |
| State | Published - Oct 24 2016 |
| Externally published | Yes |
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Keywords
- alimentary canal
- anus
- Ctenophora
- ctenophore
- evolution
- metazoan
- non-bilaterian
- through-gut
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Agricultural and Biological Sciences(all)
Cite this
The Presence of a Functionally Tripartite Through-Gut in Ctenophora Has Implications for Metazoan Character Trait Evolution. / Presnell, Jason S.; Vandepas, Lauren E.; Warren, Kaitlyn J.; Swalla, Billie J.; Amemiya, Chris T.; Browne, William.
In: Current Biology, Vol. 26, No. 20, 24.10.2016, p. 2814-2820.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The Presence of a Functionally Tripartite Through-Gut in Ctenophora Has Implications for Metazoan Character Trait Evolution
AU - Presnell, Jason S.
AU - Vandepas, Lauren E.
AU - Warren, Kaitlyn J.
AU - Swalla, Billie J.
AU - Amemiya, Chris T.
AU - Browne, William
PY - 2016/10/24
Y1 - 2016/10/24
N2 - The current paradigm of gut evolution assumes that non-bilaterian metazoan lineages either lack a gut (Porifera and Placozoa) or have a sac-like gut (Ctenophora and Cnidaria) and that a through-gut originated within Bilateria [1–8]. An important group for understanding early metazoan evolution is Ctenophora (comb jellies), which diverged very early from the animal stem lineage [9–13]. The perception that ctenophores possess a sac-like blind gut with only one major opening remains a commonly held misconception [4, 5, 7, 14, 15]. Despite descriptions of the ctenophore digestive system dating to Agassiz [16] that identify two openings of the digestive system opposite of the mouth—called “excretory pores” by Chun [17], referred to as an “anus” by Main [18], and coined “anal pores” by Hyman [19]—contradictory reports, particularly prominent in recent literature, posit that waste products are primarily expelled via the mouth [4, 5, 7, 14, 19–23]. Here we demonstrate that ctenophores possess a unidirectional, functionally tripartite through-gut and provide an updated interpretation for the evolution of the metazoan through-gut. Our results resolve lingering questions regarding the functional anatomy of the ctenophore gut and long-standing misconceptions about waste removal in ctenophores. Moreover, our results present an intriguing evolutionary quandary that stands in stark contrast to the current paradigm of gut evolution: either (1) the through-gut has its origins very early in the metazoan stem lineage or (2) the ctenophore lineage has converged on an arrangement of organs functionally similar to the bilaterian through-gut.
AB - The current paradigm of gut evolution assumes that non-bilaterian metazoan lineages either lack a gut (Porifera and Placozoa) or have a sac-like gut (Ctenophora and Cnidaria) and that a through-gut originated within Bilateria [1–8]. An important group for understanding early metazoan evolution is Ctenophora (comb jellies), which diverged very early from the animal stem lineage [9–13]. The perception that ctenophores possess a sac-like blind gut with only one major opening remains a commonly held misconception [4, 5, 7, 14, 15]. Despite descriptions of the ctenophore digestive system dating to Agassiz [16] that identify two openings of the digestive system opposite of the mouth—called “excretory pores” by Chun [17], referred to as an “anus” by Main [18], and coined “anal pores” by Hyman [19]—contradictory reports, particularly prominent in recent literature, posit that waste products are primarily expelled via the mouth [4, 5, 7, 14, 19–23]. Here we demonstrate that ctenophores possess a unidirectional, functionally tripartite through-gut and provide an updated interpretation for the evolution of the metazoan through-gut. Our results resolve lingering questions regarding the functional anatomy of the ctenophore gut and long-standing misconceptions about waste removal in ctenophores. Moreover, our results present an intriguing evolutionary quandary that stands in stark contrast to the current paradigm of gut evolution: either (1) the through-gut has its origins very early in the metazoan stem lineage or (2) the ctenophore lineage has converged on an arrangement of organs functionally similar to the bilaterian through-gut.
KW - alimentary canal
KW - anus
KW - Ctenophora
KW - ctenophore
KW - evolution
KW - metazoan
KW - non-bilaterian
KW - through-gut
UR - http://www.scopus.com/inward/record.url?scp=84994741695&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84994741695&partnerID=8YFLogxK
U2 - 10.1016/j.cub.2016.08.019
DO - 10.1016/j.cub.2016.08.019
M3 - Article
C2 - 27568594
AN - SCOPUS:84994741695
VL - 26
SP - 2814
EP - 2820
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 20
ER -