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1.
Numerous phylogenetic hypotheses have been advanced for the Malagasy lemuriform radiation, drawing on data from morphology, physiology, behaviour and molecular genetics. Almost all possible relationships have been proposed and most nodes have been contested. We present a phylogenetic analysis, using several analytical methods, of a partial sequence from the 12s rRNA mitochondrial gene. This gene codes for the small ribosomal subunit, and functional constraints require that the secondary structure of the molecule is strongly conserved, which in inturn exerts constraints on the primary sequence structure. Although previous studies have suggested a very wide range of phylogenetic applicability for this molecule, our results indicate that it is most useful in strepsirrhine primates for estimating relationships among genera within families and among relatively recently diverged families (mean sequence divergence about 11%). Relationships among families separated by larger genetic distances (>12% divergence; e.g. Cheirogaleidae, Daubentoniidae, Megaladapidae) are difficult to resolve consistently. Our data show strong support for an Indridae-Lemuridae sister group and for monophyly of the Lemuridae with Varecia as the sister to all other lemurids. They also support, albeit less strongly, sister group relationships between Lemur and Hapalemur within the Lemuridae and between PmpLthecus and Avahi in the Indridae.  相似文献   

2.
The first third (ca. 1200 bp) of exon 1 of the nuclear gene encoding the interstitial retinoid-binding protein (IRBP) has been sequenced for 12 representative primates belonging to Lemuriformes, Lorisiformes, Tarsiiformes, Platyrrhini, and Catarrhini, and combined with available data (13 other primates, 11 nonprimate placentals, and 2 marsupials). Phylogenetic analyses using maximum likelihood on nucleotides and amino acids robustly support the monophyly of primates, Strepsirrhini, Lemuriformes, Lorisiformes, Anthropoidea, Catarrhini, and Platyrrhini. It is interesting to note that 1) Tarsiidae grouped with Anthropoidea, and the support for this node depends on the molecular characters considered; 2) Cheirogaleidae grouped within Lemuriformes; and 3) Daubentonia was the sister group of all other Lemuriformes. Study of the IRBP evolutionary rate shows a high heterogeneity within placentals and also within primates. Maximum likelihood local molecular clocks were assigned to three clades displaying significantly contrasted evolutionary rates. Paenungulata were shown to evolve 2.5-3 times faster than Perissodactyla and Lemuriformes. Six independent calibration points were used to estimate splitting ages of the main primate clades, and their compatibility was evaluated. Divergence ages were obtained for the following crown groups: 13.8-14.2 MY for Lorisiformes, 26.5-27.2 MY for Lemuroidea, 39.6-40.7 MY for Lemuriformes, 45.4-46.7 MY for Strepsirrhini, and 56.7-58.4 MY for Haplorrhini. The incompatibility between some paleontological and molecular estimates may reflect the incompleteness of the placental fossil record, and/or indicate that the variable IRBP evolutionary rates are not fully accommodated by local molecular clocks.  相似文献   

3.
Host fitness is impacted by trillions of bacteria in the gastrointestinal tract that facilitate development and are inextricably tied to life history. During development, microbial colonization primes the gut metabolism and physiology, thereby setting the stage for adult nutrition and health. However, the ecological rules governing microbial succession are poorly understood. In this study, we examined the relationship between host lineage, captive diet, and life stage and gut microbiota characteristics in three primate species (infraorder, Lemuriformes). Fecal samples were collected from captive lemur mothers and their infants, from birth to weaning. Microbial DNA was extracted and the v4 region of 16S rDNA was sequenced on the Illumina platform using protocols from the Earth Microbiome Project. Here, we show that colonization proceeds along different successional trajectories in developing infants from species with differing dietary regimes and ecological profiles: frugivorous (fruit-eating) Varecia variegata, generalist Lemur catta, and folivorous (leaf-eating) Propithecus coquereli. Our analyses reveal community membership and succession patterns consistent with previous studies of human infants, suggesting that lemurs may serve as a useful model of microbial ecology in the primate gut. Each lemur species exhibits distinct species-specific bacterial diversity signatures correlating to life stages and life history traits, implying that gut microbial community assembly primes developing infants at species-specific rates for their respective adult feeding strategies.  相似文献   

4.
Short interspersed nuclear elements (SINEs) provide a near homoplasy free and copious source of molecular evolutionary markers with precisely defined character polarity. Used as molecular cladistic markers in presence/absence analyses, they represent a powerful complement to phylogenetic reconstructions that are based on sequence comparisons on the level of nucleotide substitutions. Recent sequence comparisons of large data sets incorporating a broad eutherian taxonomic sample have led to considerations of the different primate infraorders to constitute a paraphyletic group. Statistically significant support against the monophyly of primates has been obtained by clustering the flying lemur-also termed colugo-(Cynocephalus, Dermoptera) amidst the primates as the sister group to anthropoid primates (New World monkeys, Old World monkeys, and hominoids). We discovered retrotransposed markers that clearly favor the monophyly of primates, with the markers specific to all extant primates but definitively absent at the orthologous loci in the flying lemur and other non-primates. By screening the colugo genome for phylogenetic informative SINEs, we also recovered a novel family of dermopteran specific SINE elements that we call CYN. This element is probably derived from the isoleucine tRNA and appears in monomeric, dimeric, and trimeric forms. It has no long tRNA unrelated region and no poly(A) linker between the monomeric subunits. The characteristics of the novel CYN-SINE family indicate a relatively recent history. Therefore, this SINE family is not suitable to solve the phylogenetic affiliation between dermopterans and primates. Nevertheless it is a valuable device to reconstruct the evolutionary steps from a functional tRNA to an interspersed SINE element.  相似文献   

5.
Short INterspersed Elements (SINEs) make very useful phylogenetic markers because the integration of a particular element at a location in the genome is irreversible and of known polarity. These attributes make analysis of SINEs as phylogenetic characters an essentially homoplasy-free affair. Alu elements are primate-specific SINEs that make up a large portion of the human genome and are also widespread in other primates. Using a combination wet-bench and computational approach we recovered 190 Alu insertions, 183 of which are specific to the genomes of nine New World primates. We used these loci to investigate branching order and have produced a cladogram that supports a sister relationship between Atelidae (spider, woolly, and howler monkeys) and Cebidae (marmosets, tamarins, and owl monkeys) and then the joining of this two family clade to Pitheciidae (titi and saki monkeys). The data support these relationships with a homoplasy index of 0.00. In this study, we report one of the largest applications of SINE elements to phylogenetic analysis to date, and the results provide a robust molecular phylogeny for platyrrhine primates.  相似文献   

6.
Mouse lemurs (genus Microcebus) are nocturnal primates endemic to the island of Madagascar. Until recently, they were classified as two species, one from eastern and one from western Madagascar. Previously published analyses of morphometric and mitochondrial DNA data show strong support for the recognition of more than eight species, however. Here, we test the eight-species hypothesis with DNA data derived from four independently segregating nuclear loci. We find many areas of congruence between the mitochondrial and nuclear data, but incomplete lineage sorting and low mutation rates limit the phylogenetic resolution of the nuclear data. Even so, the nuclear loci unanimously find evidence for three deeply diverged lineages within the mouse lemur radiation: one that is congruent with the mtDNA "southern clade", another that is congruent with the mtDNA "northern clade", and one monospecific branch comprised of the species Microcebus ravelobensis. The latter result in particular emphasizes the need for careful biological study of this species.  相似文献   

7.
Two types (MIR and Alu) of short interspersed repeated DNA sequences (SINEs) were used for analysis of genetic relationships among higher primates, and for detection of polymorphism in human genomic DNA. The DNA regions located between the neighboring copies of these SINEs were amplified in polymerase chain reaction with primers complementary to the MIR and Alu consensus sequences (inter-SINE PCR). Comparison of the sets of amplified DNA fragments for different species or individuals provides evaluation of the relationships among them. Using inter-MIR PCR technique, the relationships among the higher primates of the infraorder Catarrhini reported elsewhere were confirmed, pointing to the efficiency of the method for phylogenetic studies. No human DNA polymorphism was revealed with the help of inter-MIR PCR. This polymorphism was detected by means of inter-Alu PCR, which is probably associated with the continuing amplification of Alu elements in human genome.  相似文献   

8.
Two types (MIR and Alu) of short interspersed repeated DNA sequences (SINEs) were used for analysis of genetic relationships among higher primates, and for detection of polymorphism in human genomic DNA. The DNA regions located between the neighboring copies of these SINEs were amplified in polymerase chain reaction with primers complementary to the MIR and Alu consensus sequences (inter-SINE PCR). Comparison of the sets of amplified DNA fragments for different species or individuals provides evaluation of the relationships among them. Using inter-MIR PCR technique, the relationships among the higher primates of the infraorder Catarrhini reported elsewhere were confirmed, pointing to the efficiency of the method for phylogenetic studies. No human DNA polymorphism was revealed with the help of inter-MIR PCR. This polymorphism was detected by means of inter-Alu PCR, which is probably associated with the continuing amplification of Alu elements in human genome.  相似文献   

9.
Female dominance or female feeding priority seem to be characteristic for many lemur species, but are rare traits in other primates and mammals in general. The nocturnal lemur species, however, are underrepresented in the quantitative studies on social dominance. The aim of this study is to investigate the pattern of intersexual dominance relationships in the gray mouse lemur (Microcebus murinus), a species that is generally thought to possess a number of ancestral lemur traits. The context, distribution, and outcome of intersexual conflicts are analyzed in four captive groups of gray mouse lemurs. Intersexual conflicts occurred in the study groups in different behavioral contexts and were mostly spatial interactions (chasing/fleeing, approach/avoidance). The majority of conflicts were decided, and were in all but one case won by females. This is the first evidence suggesting unconditional female dominance in a cheirogaleid primate. The existence of female dominance in most families of the Lemuriformes suggests it is an ancient trait that evolved in their common ancestor.  相似文献   

10.
Evidence from DNA sequences on the phylogenetic systematics of primates is congruent with the evidence from morphology in grouping Cercopithecoidea (Old World monkeys) and Hominoidea (apes and humans) into Catarrhini, Catarrhini and Platyrrhini (ceboids or New World monkeys) into Anthropoidea, Lemuriformes and Lorisiformes into Strepsirhini, and Anthropoidea, Tarsioidea, and Strepsirhini into Primates. With regard to the problematic relationships of Tarsioidea, DNA sequences group it with Anthropoidea into Haplorhini. In addition, the DNA evidence favors retaining Cheirogaleidae within Lemuriformes in contrast to some morphological studies that favor placing Cheirogaleids in Lorisiformes. While parsimony analysis of the present DNA sequence data provides only modest support for Haplorhini as a monophyletic taxon, it provides very strong support for Hominoidea, Catarrhini, Anthropoidea, and Strepsirhini as monophyletic taxa. The parsimony DNA evidence also rejects the hypothesis that megabats are the sister group of either Primates or Dermoptera (flying lemur) or a Primate-Dermoptera clade and instead strongly supports the monophyly of Chiroptera, with megabats grouping with microbats at considerable distance from Primates. In contrast to the confused morphological picture of sister group relationships within Hominoidea, orthologous noncoding DNA sequences (spanning alignments involving as many as 20,000 base positions) now provide by the parsimony criterion highly significant evidence for the sister group relationships defined by a cladistic classification that groups the lineages to all extant hominoids into family Hominidae, divides this ape family into subfamilies Hylobatinae (gibbons) and Homininae, divides Homininae into tribes Pongini (orangutans) and Hominini, and divides Hominini into subtribes Gorillina (gorillas) and Hominina (humans and chimpanzees). A likelihood analysis of the largest body of these noncoding orthologues and counts of putative synapomorphies using the full range of sequence data from mitochondrial and nuclear genomes also find that humans and chimpanzees share the longest common ancestry. © 1994 Wiley-Liss, Inc.  相似文献   

11.
The Alu repetitive family of short interspersed elements (SINEs) in primates can be subdivided into distinct subfamilies by specific diagnostic nucleotide changes. The older subfamilies are generally very abundant, while the younger subfamilies have fewer copies. Some of the youngest Alu elements are absent in the orthologous loci of nonhuman primates, indicative of recent retroposition events, the primary mode of SINE evolution. PCR analysis of one young Alu subfamily (Sb2) member found in the low-density lipoprotein receptor gene apparently revealed the presence of this element in the green monkey, orangutan, gorilla, and chimpanzee genomes, as well as the human genome. However, sequence analysis of these genomes revealed a highly mutated, older, primate-specific Alu element was present at this position in the nonhuman primates. Comparison of the flanking DNA sequences upstream of this Alu insertion corresponded to evolution expected for standard primate phylogeny, but comparison of the Alu repeat sequences revealed that the human element departed from this phylogeny. The change in the human sequence apparently occurred by a gene conversion event only within the Alu element itself, converting it from one of the oldest to one of the youngest Alu subfamilies. Although gene conversions of Alu elements are clearly very rare, this finding shows that such events can occur and contribute to specific cases of SINE subfamily evolution.  相似文献   

12.
13.
I review new evidence on origins and adaptive radiation of Malagasy lemurs, a remarkably diverse group containing 13% of living primate species. The number of recognized lemur species has increased significantly, partly due to research revealing specific subdivisions within known populations but mainly because of discovery of new populations through fieldwork. Some species feared to be extinct have also been rediscovered. Specific numbers have increased particularly in small-bodied, cryptic genera for which continued research will surely reveal even more species.Adaptative radiation of lemurs has been essentially confined to Madagascar. The high density of lemur species on that island, associated with very small geographical ranges, has major implications both for their evolutionary divergence and for conservation. Reconstructions of phylogenetic relationships among primates have been considerably enhanced by DNA sequence data. Sufficient data are now available from both nuclear and mitochondrial sequences to examine relationships among and within the major groups of living primates. Most studies have confirmed that lemurs constitute a monophyletic sister-group of the lorisiform clade and all exclude a specific relationship between cheirogaleids and lorisiforms repeatedly inferred from morphological evidence. However, some analyses indicate that the aye-aye may have branched away before the divergence between other lemurs and lorisiforms. DNA sequence analyses have also yielded a broad consensus for relationships between Eulemur, Hapalemur, Lemur and Varecia: Varecia branched away first, while Lemur is more closely related to Hapalemur than to Eulemur. As debate about phylogenetic relationships among lemurs and other primates seems to have been settled in favor of lemur monophyly (possibly excluding the aye-aye), only a single invasion of Madagascar is required; but it must still be explained how ancestral lemurs could have migrated there at an appropriate time. Separation between Madagascar and Africa was apparently complete by about 120 Ma, too far in the past for direct overland migration. A recent hypothesis suggested that uplifted land in the Mozambique Channel assisted colonization of Madagascar 26-45 Ma, seemingly agreeing with an estimated date of about 40 Ma for divergence of lemurs from other primates. However, mounting evidence suggests that divergence occurred significantly earlier. Because the earliest known fossil representatives of several modern orders of placental mammals (including primates) are dated no earlier than the early Tertiary, it is widely accepted that their divergence took place after the Cretaceous/Tertiary mass extinction. Yet the known fossil record can only yield minimum divergence times; if sampling is poor and/or biased there may be a considerable discrepancy between minimum and actual dates. There is, for example, virtually no known fossil record for lemurs in Madagascar and the earliest known representatives are subfossil lemurs, so in this case a direct reading of the fossil record would indicate that the lemurs first originated just a few thousand years ago! Examination of underestimation of times of origin because of poor sampling in the fossil record has confirmed previous suggestions that primates originated considerably earlier than generally believed. Several recent phylogenetic reconstructions based on DNA sequence data and using calibration dates derived from groups other than primates provide independent support for this inference. Overall, it now seems that primates originated at around 90 Ma rather than the 55 Ma indicated by direct reading of the known fossil record. Hence, colonization of Madagascar by lemurs would have taken place at about 80 Ma, double the date usually accepted, and should be interpreted in terms of contemporary continental relationships.  相似文献   

14.
The Alu Ya-lineage is a group of related, short interspersed elements (SINEs) found in primates. This lineage includes subfamilies Ya1-Ya5, Ya5a2 and others. Some of these subfamilies are still actively mobilizing in the human genome. We have analyzed 2482 elements that reside in the human genome draft sequence and focused our analyses on the 2318 human autosomal Ya Alu elements. A total of 1470 autosomal loci were subjected to polymerase chain reaction (PCR)-based assays that allow analysis of individual Ya-lineage Alu elements. About 22% (313/1452) of the Ya-lineage Alu elements were polymorphic for the insertion presence on human autosomes. Less than 0.01% (5/1452) of the Ya-lineage loci analyzed displayed insertions in orthologous loci in non-human primate genomes. DNA sequence analysis of the orthologous inserts showed that the orthologous loci contained older pre-existing Y, Sc or Sq Alu subfamily elements that were the result of parallel forward insertions or involved in gene conversion events in the human lineage. This study is the largest analysis of a group of "young", evolutionarily related human subfamilies. The size, evolutionary age and variable allele insertion frequencies of several of these subfamilies makes members of the Ya-lineage useful tools for human population studies and primate phylogenetics.  相似文献   

15.
Although a general agreement on the major groups of eutherian orders and their phylogenetic affiliations is emerging, the evolutionary affiliations among the members constituting these groups are still subject to debate. A prominent example is the recently published molecular evidence that challenges the long assumed monophyly of primates, displaying the colugo or flying lemur (Cynocephalus, Dermoptera) as a sister to anthropoid primates (Arnason et al. 2002 ) and positioning them after the prosimian primates (tarsiers and strepsirhines) split off. The phylogenetic analysis of the complete mitochondrial (mt) genome sequence of Cynocephalus variegatus presented in this study first appears to corroborate interpretations of primates as a paraphyletic group. However, more detailed analyses disclosed that mt nucleotide composition and consequently amino acid (AA) composition varied considerably among the species analyzed. This led us to assume that the flying lemur may be incorrectly grouped with anthropoids on the basis of similar mt nucleotide and AA compositions, rather than reflecting the true evolutionary relationship. To reanalyze the flying lemur's evolutionary association with other eutherian orders from a completely different molecular perspective, a molecular cladistic approach was applied. To this end, we determined the presence/absence pattern of transposable elements that provide a nearly homoplasy-free and copious source of molecular evolutionary markers, with well-defined character polarity. We could identify transposable elements, both on a multilocus and single-locus level, being present in all extant primate infraorders but absent in the flying lemur, thus clearly supporting the monophyly of primates by retropositional evidence.  相似文献   

16.
MHC class I cDNA sequences from the most divergent primate group of extant primates compared to human, the suborder Strepsirrhini (prosimians), are described. The sequences are derived from the gray mouse lemur (Microcebus murinus) and the ring-tailed lemur (Lemur catta), which are members of the malagasy Lemuriformes, as well as from the pygmy slow loris (Nycticebus pygmaeus), a prosimian from East Asia. The M. murinus sequences have been analyzed in detail. Analysis of the expression level, G/C content, and synonymous vs. nonsynonymous substitution rates in the peptide-binding region codons suggests that these cDNA clones represent classical class I (class Ia) genes. According to Southern blot analysis, the genome of the gray mouse lemur might contain about 10 class I genes. In gene tree analysis, the strepsirrhine class Ia genes described here cluster significantly separately from the known class I genes of Catarrhini (humans, apes, Old World monkeys) and Platyrrhini (New World monkeys) species, suggesting that the class I loci of Simiiformes arose by gene duplications which occurred after the divergence of prosimians.  相似文献   

17.
The lemurs of Madagascar are known for their extraordinary species diversity. The mechanisms that allow the coexistence of these species are still poorly known. Here feeding patterns were investigated for three small nocturnal lemur species of Cheirogaleidae ( Microcebus murinus , Cheirogaleus medius and Cheirogaleus major ) occurring sympatrically in a littoral rainforest in south-east Madagascar. During three rainy seasons, the plant species eaten by these three lemurs were described in relation to morphological and biochemical characteristics. All three species were mainly frugivorous and fed on 68 different plant species with small- and medium-sized fruits. A total of 91% of these forage plant species was visited by all three lemur species. Fruits larger than 25–30 mm were avoided. Seeds of a total of 51 food plant species were swallowed and passed the gut unharmed. Thus, even these smaller lemur species play an important role in seed dispersal. There were no differences in the morphological and biochemical characteristics of fruits eaten between the three species, but the feeding height was significantly different between the species. Thus, competition avoidance and niche separation are presumably not based on different feeding patterns of M. murinus , C. medius and C. major in the littoral rainforest, but on different habitat utilization.  相似文献   

18.
R-banding chromosomal studies of 21 species of Lemuriformes allowed us to reconstruct the presumed ancestral karyotype of all the Lemuriformes except for Daubentoniidae and permitted the construction of their phylogenetic tree. Chromosome painting with fluorescently labeled heterologous DNA probes permitted comparative chromosome maps to be established. The Zoo-FISH method was used to reassess the karyotypes of 22 species or subspecies. While our results largely confirm the previous reconstruction of the ancestral karyotype, they resulted in a modification of the previously established phylogenetic tree. The Daubentoniidae emerged first followed by the divergence of the families Cheirogaleidae, Indriidae, Lepilemuridae and Lemuridae. Eight chromosome rearrangements occurred in all Lemuriformes except for Daubentoniidae in the common trunk. The present findings do not allow us to propose the occurrence of any rearrangement common to Daubentoniidae and other Lemuriformes, and probably other Prosimii. Conserved syntenies previously described in various mammalian orders were also conserved, while others were specific to the Lemuriformes.  相似文献   

19.
In these postgenomic times where aspects of functional genetics and character evolution form a focal point of human-mouse comparative research, primate phylogenetic research gained a widespread interest in evolutionary biology. Nevertheless, it also remains a controversial subject. Despite the surge in available primate sequences and corresponding phylogenetic interpretations, primate origins as well as several branching events in primate divergence are far from settled. The analysis of SINEs - short interspersed elements - as molecular cladistic markers represents a particularly interesting complement to sequence data. The following summarizes and discusses potential applications of this new approach in molecular phylogeny and outlines main results obtained with SINEs in the context of primate evolutionary research. Another molecular cladistic marker linking the tarsier with the anthropoid primates is also presented. This eliminates any possibility of confounding phylogenetic interpretations through lineage sorting phenomena and makes use of a new point of view in settling the phylogenetic relationships of the primate infraorders.  相似文献   

20.
The alarming rate of deforestation in Madagascar is driving some endemic primates to extinction. Surprisingly, anthropogenic habitat disturbance is not always deleterious. The effect of disturbance on lemur abundance may be related to diet, with frugivorous species more prone to population declines than folivores or insectivores. To test the effects of disturbance on lemur abundance and group size, we surveyed 2 sites within contiguous forest at Ranomafana National Park, 1 lightly disturbed primary forest (Vato) and 1 heavily logged forest (Tala). We quantified forest structure variables along 6 survey routes and conducted 68 diurnal and 42 nocturnal lemur surveys. Canopy closure, canopy height, and understory visibility were greater in Vato than in Tala. We encountered 2 frugivorous lemurs (Eulemur rufifrons, Varecia variegata) and 1 folivore (Avahi peyrierasi) significantly more frequently in Vato than in Tala, whereas the opposite was true for the insectivorous Microcebus rufus. Rates did not differ statistically for 1 frugivore (Eulemur rubriventer) and 2 folivores (Propithecus edwardsi, Hapalemur griseus). Comparisons across the 6 survey routes suggest that the abundance was heterogeneous within as well as between sites. Neither group size nor composition differed between sites. Encounter rates for Varecia variegata were positively related to canopy closure, and encounter rates for Avahi peyrierasi were positively related to canopy height. Encounter rates for Microcebus rufus were negatively related to canopy closure, height, and understory visibility. Similar to other studies, the results suggest that some lemurs, including folivores, may cope with anthropogenic disturbance better than others, including some frugivores. Lemur abundance is heterogeneous, though, even on small spatial scales.  相似文献   

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