Evolution in the Murinae (Rodentia) Assessed by Microcomplement Fixation of Albumin

The inter-relationship of 17 genera of Murinae rodents were studied using microcomplement fixation of albumin to measure immunological distances among taxa. The genera chosen represented six major clades and four monogeneric groups identified in earlier companion studies (an African group, a South-east Asian group, a New Guinean group, an Australasian group, an Acomys group, a Micromys group and Apodemus, Millardia, Mus and Phloeomys). When these companion studies are included 136 species and 67 genera were studied. Ten major clades were consistently supported by the data but apart from linking the South-east Asian and Australasian clades, the data do not resolve their inter-relationships. The Acomys-Uranomys-Lophouromys clade may be the sister-group to the rest of the Murinae. Otomys (Otomyinae) is considered to be a murine related to the African group of genera. Of the ten major clades identified, only one (Mus) occurs significantly in more than one primary biogeographic region. It is suggested that following an early period of relatively rapid dispersal from the place of origin, little further dispersal took place and subsequent evolution occurred within relatively confined geographic areas.

Evolution in Some South-East Asian Murinae (Rodentia), as Assessed by Microcomplement Fixation of Albumin, and Their Relationship to Australian Murines

The interrelationships of 16 genera and 49 species of predominantly South-east Asian murine rodents were studied by means of microcomplement fixation of albumin to measure immunological distances among taxa. The results are viewed as a hypothesis of the phylogenetic relationship of these taxa that can be tested by other data sets. Three main groupings are suggested: (1) Maxomys; (2) Leopoldomys, Niviventer and Tokudaia; and (3) Bandicota, Berylmys, Bullimus, Bunomys, Komodomys, Nesokia, Papagomys, Paruromys, Rattus, Stenomys, Sundamys and Taeromys. Within this latter group, Bunomys chrsogasta, Komodomys and Rattus timorensis group together, as do Bullimus, Rattus and Stenomys, and Bandicota with Nesokia. The Australian murines, represented by Mesembriomys, may be part of this South-east Asian radiation but, if so, arose early in its history. Biogeographically, the results support South-east Asia as being a centre of murine evolution with secondary foci in Sulawesi, New Guinea and Australia. There is some evidence to suggest that a relatively recent land bridge between Sulawesi, Flores and Timor may have existed.

Evolution in New-Guinean Muridae (Rodentia) Assessed by Microcomplement Fixation of Albumin

The interrelationships of 19 genera and 28 species of New Guinean rodents representing 80% of the currently recognised New Guinean genera, were studied using microcomplement fixation of albumin to measure immunological distances among genera. The phylogenetic distinctiveness of Rattus and the closely related Stenomys from all other genera was confirmed. The remaining genera fall into three groups: (i) Lorentzimys; (ii) Anisomys, Coccymys, Chiruromys, Hyomys, Macruromys, Mallomys and Pogonomys; and (iii) Crossomys, Hydromys, Leptomys, Mayermys, Melomys, Neohydromys, Parahydromys, Pseudohydromys and Uromys. Solomys, from the Solomon islands, and Leggadina, Mesembriomys and Xeromys, from Australia, were shown to belong to this latter group. Groups (i) and (ii) are essentially endemic to New Guinea, while the third shares genera and species with Australia.

The Evolution of Species of the Varanidae - Microcomplement Fixation Analysis of Serum Albumins

Phylogenetic relationships among 30 of the 40 species in the Varanidae were examined in the light of molecular information on albumin evolution derived from microcomplement fixation. A phylogeny based on these results is compared with proposed phylogenies based on data obtained using other techniques. Three separate radiations of Varanus are found in Australia, The movement of varanids to Australia from south-east Asia is thought to have occurred approximately 15-20 million years ago.

Rates of Albumin Evolution in Parrots (Aves, Psittaciformes)

A number of lines of evidence suggest that the rate of molecular evolution in birds is slower than in other vertebrates. This hypothesis was tested by measuring the extent of amino-acid sequence divergence in albumin among species of parrots by means of microcomplement fixation. This group was chosen because its modern distribution is strongly suggestive of a Gondwanan origin. The results show that the intercontinental albumin distances are well below those expected for a Gondwanan group. These data are in accord with the hypothesis that birds have a slower rate of molecular evolution, although other explanations are possible.

Evolutionary Relationships of the Australasian Mud-Nesters (Grallinidae, Corcoracidae) - Immunological Evidence

The phylogenetic relationships of the genera of Australasian mud-nesters (Corcorax, Struthidea and Grallina) were examined by microcomplement fixation, and the results compared with morphological and DNA-DNA hybridisation data. There was general corroboration among all data sets such that (1) Corcorax and Struthidea were well-diverged members of a single lineage related to corvoids, and (2) Grallina comprised two species (Australian G. cyanoleuca and New Guinean G. bruijni) closely allied to Myiagra among the monarch flycatchers (Monarchidae). The immunological data also indicated that Corcorax and Struthidea were closer to Corvus (Corvinae) than to some other members of that subfamily identified by DNA-DNA hybridisation. There was further corroboration of evidence from DNA-DNA hybridisation for an endemic radiation among Australo-Papuan passerine families.

DNA-DNA Hybridization and the Position of Leadbeater Possum (Gymnobelideus-Leadbeateri Mccoy) in the Family Petauridae (Marsupialia, Diprotodontia)

The diprotodontian family Petauridae is composed of two subfamilies: Petaurinae (gliders) and Dactylopsilinae (striped possums). Leadbeater's possum (Gymnobelideus leadbeateri) has generally been placed among the petaurines on the basis of morphological, particularly dental, characters. Recent microcomplement fixation data, however, suggest that G. leadbeateri is a sister group to the Dactylopsilinae. We report DNA-DNA hybridisation comparisons among Leadbeater's possum, two dactylopsilines, two petaurines, and an outgroup pseudocheirid. Phylogenetic analysis of these data support the basic dichotomy between petaurines and dactylopsilines, and suggest that G. leadbeateri is more closely related to dactylopsilines. Resolution of this relationship, assayed by bootstrap analysis, is limited, but branch lengths on the optimal tree suggest a rapid initial diversification of three lineages within the Petauridae: dactylopsilines, petaurines and G. leadbeateri.

Phylogeny of the Australian Rodents (Muridae) - a Molecular Approach Using Microcomplement Fixation of Albumin

Microcomplement fixation was used to assess albumin evolution in the history of the rodents of Australia. The results confirmed a monophyletic grouping consisting of the genera Pseudomys, Mastacomys and Notomys, and showed that the genus Pseudomys is paraphyletic. The genera Conilurus, Leporillus and Mesembriomys also formed a monophyletic group. A significant finding was that Leggadina was distantly related to all Pseudomys species, and indeed may be the earliest offshoot of all Australian rodents other than Rattus. Albumin evolution in the Australian rodents has occurred in a manner far from clock-like. Mastacomys Thomas, 1882 is synonymised with Pseudomys Gray, 1832.

Immunological Evolution of Albumin in the Estrildine Finches (Aves, Passeriformes) Is Far From Clock-Like

On the basis of microcomplement fixation studies, the finch Taeniopygia guttata has an albumin whose immunological properties are very different from those of other finches. Outgroup analysis, microcomplement fixation of transferrin, and electrophoretic behaviour of finch albumin, together with phylogenetic considerations based upon chromosomes and allozymes, revealed that the difference is due to rapid change in the immunological properties of T. guttata albumin rather than to a distant relationship of T. guttata to other finches. Indeed, the immunological properties of the albumin of T. guttata has undergone about 15 times as much change as would be expected for an albumin clock. The results highlight the caution that should be exercised when applying the molecular clock ad hoc to immunological data.