Molecular systematics and evolution in New Zealand: Applications to cryptic skink species

Abstract

The polymerase chain reaction (PCR) and DNA sequencing are being used for the study of the origin and evolution of New Zealand plants and animals. Here we describe methods for rapidly obtaining DNA sequences from small amounts of fresh and preserved tissue, and apply them to the problem of resolving relationships among skinks of the Austrnlasian genus Leiolopisma. DNA extracted from frozen tail muscle was used for the main part of the study. Part of the mitochondrial12S ribosomal RNA gene was isolated using PCR. Direct sequencing of this 400 nucleotide region supports the separation of "L. nigriplantare" into several genetically distinct but morphologically similar species. The sequence data have also identified a potential case of hybridisation between two sympatric species in Otago, L. nigriplantare polychroma and L. maccanni. The data set supports the view that skinks have been in New Zealand very much longer than five million years.From these results we expect that application of the PCR and other techniques in molecular biology will help solve many questions about the origins and evolution of New Zealand's biota, as well as help identify unique populations for conservation.

Rapid Speciation, Morphological Evolution, and Adaptation to Extreme Environments in South African Sand Lizards (Meroles) as Revealed by Mitochondrial Gene Sequences

“…This possibility has also been suggested in other cases (Freisen et al, 1996;Lara et al, 1996), including one where sequence data from the 12S gene failed to resolve relationships in scincid lizards of the genus Leiolopisma (Hickson et al, 1992).…”

“…Lacerta lepida was used as an outgroup. Both these gene regions have been used for investigating intrafamilial and intrageneric relationships in other lizards (Hedges et al, 1991;Hickson et al, 1992;Hedges and Bezy, 1994;Thorpe et al, 1994;Gonzalez et al, 1996).…”

Some recent progress with methods for evolutionary trees

“…With most real data the i.i.d model is too simple and the signals will be more complex. An example is a dataset with 10 New Zealand Leiolopisma skinks (see Hickson et al 1992) where there are many more apparent signals in the data (Fig. 7).…”

“…The lizards are all New Zealand skinks and, except for one Cye/odina species (number 5), are Leiolopisma species. They are: (I) an undescribed slUnk "Stewart Island Green"; (2) another undescribed species "Ll2I8"; (3) L. grande; (4) L. microlepis; (5) Cye/odina aenea; (6) L. incompicuum; (7) L. zelandicum; (8) L. maccanni; (9) L. nigriplantare polychroma (from Twizel); (10) L. otagense (see Daugherty et al 1990 andHickson et al 1992 Table 4 Numbers of times each taxon is in an excluded partition. For each taxon "exc" is the number of times it is in a partition not selected (excluded) from the optimal tree in Fig.…”

“…The sequence data used in this study come from the following sources: sequences used to study the origin of the green plant chloroplasts ; ribosomal RNA sequences from New Zealand skinks (Hickson et al 1992); and sequences from a hemoglobin pseudogene from five primates (Miyamoto et al 1988). …”