Ribosomal DNA and RAPD Variation in the Rare Plant Family Lactoridaceae

Abstract

Lactoris fernandeziana, endemic to the island of Masatierra in the Juan Fernandez Archipelago, is the only living member of the primitive angiosperm family, Lactoridaceae. The species was surveyed for ribosomal DNA (rDNA) and RAPD (Random Amplified Polymorphic DNA) variation. Previous analyses of allozymes had revealed no variation within the species. Variation was found for length in the intergenic spacer and for restriction sites in the 18S–25S genes of rDNA, and for the presence of amplified bands using 16 primers. Different rDNA repeat lengths and restriction site variants were detected within individuals as well as within and among populations. The level of variation in RAPDs is low relative to other Juan Fernandez endemic species surveyed, and nearly all variants were restricted to single populations. The rDNA length variants were distributed throughout the island, whereas the rDNA restriction site variants and RAPD markers indicated minor genetic differences among the populations.

Clonal diversity in the rareCalamagrostis porterissp.insperata(Poaceae): comparative results for allozymes and random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) markers

“…However, it is now evident that allozymes may underestimate genetic diversity in plant populations and species because additional diversity has been detected when other molecular markers were employed. Examples are available from genera such as Trifolium (Hickey et al 1991; Hickey & Vincent 1992; Crawford et al 1998), Lactoris (Brauner et al 1992; Crawford et al 1994) and Penstemon (Wolfe & Elisens 1993; Wolfe et al 1998a,b). Ellstrand & Roose (1987) concluded, from their survey of published studies, that the greater number of characters used, whether of the same type (such as number of allozyme loci) or of different types, the more diversity encountered.…”

Patterns of genetic and phenotypic variation inIris hayneiandI. atrofusca(Irissect.Oncocyclus = the royal irises) along an ecogeographical gradient in Israel and the West Bank

“…Some narrow endemics have been shown to have strong genetic structure among populations despite being restricted to specialized ecosystems (Brauner et al . 1992; Travis et al .…”

Population genetic structure of two rare tree species (Colubrina oppositifoliaandAlphitonia ponderosa, Rhamnaceae) from Hawaiian dry and mesic forests using random amplified polymorphic DNA markers

“…They have also been characterized as being genetically depauperate due to the recency of the founding event, isolation from source population, occurrence of stochastic processes and populations limited by size and distribution within the island environment (Carlquist 1980; Crawford et al . 1987a, 1988, 1990; Brauner et al . 1992; Elisens 1992).…”