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Titolo:
A molecular phylogenetic analysis of reproductive trait evolution in the soft coral genus Alcyonium
Autore:
McFadden, CS; Donahue, R; Hadland, BK; Weston, R;
Indirizzi:
Harvey Mudd Coll, Dept Biol, Claremont, CA 91711 USA Harvey Mudd Coll Claremont CA USA 91711 ept Biol, Claremont, CA 91711 USA
Titolo Testata:
EVOLUTION
fascicolo: 1, volume: 55, anno: 2001,
pagine: 54 - 67
SICI:
0014-3820(200101)55:1<54:AMPAOR>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
XENIA-MACROSPICULATA GOHAR; LIFE-HISTORY EVOLUTION; RED-SEA; MARINE-INVERTEBRATES; SIDERIUM VERRILL; BENTHIC INVERTEBRATES; SEQUENCE ALIGNMENT; LARVAL DEVELOPMENT; JUVENILE ECOLOGY; MATING SYSTEMS;
Keywords:
Alcyonium; cnidarian; internal transcribed spacer; larval development; life-history evolution; molecular systematics; ribosomal DNA; sexual expression; soft coral;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
90
Recensione:
Indirizzi per estratti:
Indirizzo: McFadden, CS Harvey Mudd Coll, Dept Biol, Claremont, CA 91711 USA Harvey Mudd Coll Claremont CA USA 91711 remont, CA 91711 USA
Citazione:
C.S. McFadden et al., "A molecular phylogenetic analysis of reproductive trait evolution in the soft coral genus Alcyonium", EVOLUTION, 55(1), 2001, pp. 54-67

Abstract

The soft coral genus Alcyonium is among the most reproductively diverse invertebrate taxa known: The genus includes species that vary both in mode ofreproduction (including broadcast spawners, internal brooders, and external brooders) and sexual expression (gonochores, hermaphrodites, and a unisexual parthenogen). Such diversity offers a unique opportunity to examine associations between reproductive and morphological traits in a phylogenetic context. We used an approximately 900-bp sequence of the nuclear ribosomal gene complex spanning the internal transcribed spacer (ITS) regions to construct a molecular phylogeny for 14 European and North American species of Alcyonium onto which we mapped the known distribution of reproductive and morphological traits. The phylogeny suggests that hermaphroditism or parthenogenesis has evolved independently at least twice in this genus, and always in internally brooding species. Broadcast spawning and external brooding only occur in species with large colony size, whereas all species with small colony size brood their larvae internally. Internal brooding and small size appear to be ancestral in this genus; if this is the case, an association between broadcast spawning and large colony size has evolved independently in at least two clades. This tendency of small adults to brood their larvae while large adults broadcast spawn them into the plankton has been observedin a variety of solitary invertebrate taxa, but to date has not been documented in any other colonial invertebrates. Moreoever, it has been suggestedthat organisms with a colonial growth form should not experience the allometric constraints on brood space that have been proposed to explain the association between adult size and mode of reproduction in solitary organisms. Unlike many other colonial groups, however, module (polyp) Size is strongly correlated with colony size in Alcyonium, and constraints on brooding maybe imposed by module, rather than colony, allometry. The very close genetic relationship (< 1% sequence divergence) and shared polymorphisms among A.digitatum (a large, gonochoric broadcast spawner), A. siderium, and A. sp. A (intermediate-sized and small hermaphroditic, internal brooders) suggestthat evolutionary transitions between broadcast spawning and brooding and between gonochorism and hermaphroditism can occur easily and rapidly in this group.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 10/07/20 alle ore 12:54:25