From: PO2::"BOLTON@botzoo.uct.ac.za" "BOLTON, J, JOHN, ASSOC.PROF" 12-APR-1995 03:36:16.31 To: Multiple recipients of list ALGAE-L CC: Subj: A kingdom for the Rhodophytes Dear phycologists I am just doing my annual revision of lecture notes for a second year course, and decided to try to be as accurate as possible on relationships between algal Divisions (trying to replace the dreaded Protista in the students' minds). I am searching for a system at the Kingdom level, which gives some real framework from our knowledge of relationships (or mostly lack of them) between Divisions. The best seems to me to be the Cavalier-Smith version (with additions), roughly as below: Kingdom Green plants Plantae (including Chlorophyta [with old Charophyta] etc.) browns, diatoms etc. etc. Chromista (trying to avoid the stramenopiles - ugly name), euglenoids and dinoflagellates Protozoa Blue-greens Prokaryota (Cyanoprokaryota!) My problem is the Rhodophyta, which Cavalier-Smith apparently once placed in the Subkingdom Biliphyta of the Plantae. Is there any supporting evidence for this (certainly distant) suggested link between rhodophytes and the green plants? (In other words that the reds are more closely related to the Plantae than to any of the other groups mentioned above). It seems to me from molecular evidence to date that the reds deserve their own Kingdom. Has anyone given it a name yet? The red algal biologists seem to go out of their way to avoid the issue at this stage. Any discussion would be welcome - sounds like a good topic for ALGAE-L to me. Best wishes John Bolton A/Prof John J. Bolton Head, Botany Department University of Cape Town Rondebosch 7700 South Africa E-mail: BOLTON@BOTZOO.UCT.AC.ZA From: PO3::"delwiche@bio.indiana.edu" 12-APR-1995 15:11:24.86 To: Multiple recipients of list ALGAE-L CC: Subj: Re: A kingdom for the Rhodophytes I tend to agree that the reds should have their own kingdom name, although I hate to see too many nomenclatural changes made before the phylogeny is really sorted out. Molecular systematics has provided a lot of new information, but the branching order in the "crown of eukaryotic diversity" remains very poorly known. I think Cavalier-Smith puts the reds in the Kingdom Plantae largely because they, like greens, have what seem to be primary plastids, and there is a moderate amount of evidence suggesting that all primary plastids are monophyletic. If plastids really are monophyletic, then it might make sense to put everything with plastids into a single kingdom, but that ignores the possibility that some major groups have secondarily lost plastids. If one is going to accept the current molecular phylogenies at face value then the easiest explanation would probably require several losses of plastids in the crown groups, or else two or three separate origins of plastids from very closely related cyanobacteria. It is clear, however, that red algae are a coherent group and branch deeply within the crown eukaryotes, so I would be inclined to give them a kingdom name no matter what their close relatives are. I don't know of anyone who has given them a formal kingdom name. Chuck Delwiche -- Charles F. Delwiche -- delwiche@bio.indiana.edu Dept. of Biology, JH 142, I.U. phone: (812) 855-2549 Bloomington, IN 47405 FAX: (812) 855-6705 "Well, if you wanted to make Serac the Preparer cry, mission accomplished." From: PO2::"Mark@imb.lan.nrc.ca" "Ragan, Mark A." 12-APR-1995 19:53:25.23 To: Multiple recipients of list ALGAE-L CC: Subj: A kingdom for the red algae? John Bolton (bolton@botzoo.uct.ac.za) has recently posted some questions about relationships between red algae and other eukaryotes. A growing amount of molecular-sequence evidence bears on this point. JB writes: I am searching for a system at the Kingdom level, which gives some real framework from our knowledge of relationships (or mostly lack of them) between Divisions. MR replies: Any attempt to reconstruct natural relationships among algal Divisions, while ignoring other protists, is doomed to failure. Depending on how one defines defines the term, "algae" have arisen as many as five times (cyanobacteria; euglenoids; dinoflagellates; chromophytes; reds and greens)...or perhaps more, depending on where some minor groups eventually end up in The Big Tree. JB: The best seems to me to be the Cavalier-Smith version (with additions)... My problem is with the Rhodophyta, which Cavalier-Smith apparently once placed in the Subkingdom Biliphyta of the Plantae. MR: Mike Dick (University of Reading) tells me that "stramenopiles" is properly spelled "straminipiles"; I agree, it's an ugly word. The Cavalier-Smith scheme you cite was published in BioSystems 14: 461-481, 1981. JB: Is there any supporting evidence for this (certainly distant) suggested link between rhodophytes and the green plants? (In other words that the reds are more closely related to the Plantae than to any of the other groups mentioned above). MR: Yes, there is now reasonably strong evidence that red algae and the green alga - green plant line are sister groups, i.e. descended from a unique common ancestor. The evidence is: a) 18S rDNA sequences; b) GAPDH-A and, more problematically, GAPDH-C sequences; c) TPI protein trees; d) cox3 gene sequences; e) immunological crossreactivities among RuBP carboxylase large subunit proteins; f) patterns of polyadenylation in nuclear protein-coding genes; g) presence of only two membranes around plastids. The argument has been summarized by myself and Robin R. Gutell, "Are red algae plants?", in press at the Botanical Journal of the Linnean Society, where all relevant publications (many still in press) are cited. Further unpublished work (from another group) is mentioned there too. The link isn't so distant when the scope of eukaryotic life is considered. JB: It seems to me from molecular evidence to date that the reds deserve their own Kingdom. Has anyone given it a name yet? The red algal biologists seem to go out of their way to avoid the issue at this stage. MR: As you may know, I'm an agnostic on higher-level classification. However, Carolyn Bird, Ellen Rice Kenchington, Robin Gutell and I proposed the Kingdom Rhodophyta, somewhat (but not entirely) tounge-in-cheek, in our paper at the Fourth International Phycological Congress. Anyone grappling with Kingdom Rhodophyta will have to concern her/himself with the cryptomonad (and perhaps chlorarachniophyte) nucleomorphs (and, by extension, with part of the cryptomonad genome) and with glaucophytes ("The transition between Glaucophyceae and Rhodophyceae is so gradual that they might almost be treated as a single class" -- Cavalier-Smith, Evol. Trends Plants 2: 75-78, 1987). Another reason to keep that protistological perspective! Very best regards, Mark Ragan NRC Institute for Marine Biosciences Halifax, Nova Scotia, Canada tel 902-426-1674 fax 902-426-9413 e-mail mark@imb.Lan.nrc.ca