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PubMed1976

The phylogeny and ontogeny of humeral torsion.

In a series of specimens extending from fossil material through recent vertebrates including man there occurs a gradual phylogenetic increase in the degree of humeral torsion. A further (ontogenetic) torsion is superimposed upon the phylogenetic one in man which increases from birth until the proximal epiphysial cartilage of the humerus disappears and bony fusion occurs. There is a distinct correlation between the calculated strength of humeral rotator muscles inserting above and below the proximal epiphysis; this suggests that they provide the forces involved in the production of humeral torsion. It is shown that ontogenetic or secondary torsion occurs proximally and not along the shaft of the bone. Differences in the degree of humeral torsion in either sex of adult Whites and Negroes are given and discussed.

Adult↗
PubMed1977

The free swimming Pipa larvae, with a review of pipid larvae and pipid phylogeny (Anura: Pipidae).

This paper describes the morphology of the free swimming Pipa larvae, compares them with Xenopus, Hymenochirus, and to some extent, Rhinophrynus larvae, and presents a morphological diagnosis of pipid larvae. Pipa and Xenopus have very similar chondrocrania. Hymenochirus is superficially different but has the same diagnostic features. The differences appear related to its small size and predatory habitus. Other aspects of anatomy, especially the filter apparatus are very different in each genus. The filter apparatus of Pipa is somewhat reduced and seems modified for the retention of relatively large (20+ microns) particles. Similar adaptations may have been annectant to predations in Hymenochirus, which lacks a filter apparatus. However, varying states of seven character complexes, which cut across the varying ecology, show that there are two basic pipid lineages, each currently confined to Africa or South America, respectively. Recent finds of fossil South American Xenopus indicate that these two lineages separated before the continents did. This does not warrant the recognition of two subfamilies because Xenopus and Hymenochirus are too different. Pseudhymenochirus is not an intermediate between them; it is primitive Hymenochirus. Eight character states separate pipid and rhynophrynid larvae.

Animals↗
PubMed1979

Chromosomal evolution in primates: tentative phylogeny from Microcebus murinus (Prosimian) to man.

The karyotypes of more than 60 species of Primates are studied and compared, with the use of almost all existing banding techniques. There is a very close analogy of chromosome banding between the Simians studied and man. The quantitative or qualitative variations detected all involve the heterochromatin. It is very likely that all the euchromatin (nonvariable R and Q bands) is identical in all the species. Approximately 70% of the bands are common to the Simians and to the Lemurs (Prosimians). In the remaining 30%, technical difficulties prevented a valuable comparison, but this does not exclude the possibility that a complete analogy may exist. Thus, it is very likely that chromosomal evolutions of the Simians, and probably of all the Primates, has occurred without duplication or deficiency of the euchromatin. Approximately 150 rearrangements could be identified and related to the human chromosomes. The types of rearrangement vary from one group (suborder, family, genus) to another. For instance, Robertsonian translocations are preponderant among the Lemuridae (44/57), but are nonexistent among the Pongidae. Chromosome fissions are very frequent amng the Cercopithecidae (10/23), but were not found elsewhere, and pericentric inversions are preponderant in the evolution of Pongidae and man (17/28). This suggest that the chromosomal evolution may be directed by the genic constitution (favouring the occurrence of a particular type of rearrangement, by enzymatic reaction), by the chromosomal morphology (the probability that Robertsonian translocation will be formed depends at least partially on the number of acrocentrics), and by the reproductive behaviour of the animals. Reconstitution of the sequence of the chromosomal rearrangements allowed us to propose a fairly precise genealogy of many Primates, giving the positions of the Catarrhines, the Platyrrhines, and the Prosimians. It was also possible to reconstruct the karyotypes of ancestors that died out several dozen million years ago. The possible role of chromosomal rearrangements in evolution is discussed. It appears necessary to consider different categories of rearrangements separately, depending on their behaviour. The 'nonfavoured' rearrangements, such as pericentric inversions, need to occur in an isolated small population for implanting, by an equivalent of genic derivation. The 'favoured' rearrangements, e.g., Robertsonian translocations, may occur and diffuse in panmictic populations, and accumulate. Their role of gametic barrier could be much more progressive. For discrimination between these two categories, it was necessary to differentiate the selective advantage or disadvantage of the rearrangement itself. It was not possible to show that chromosomal rearrangements play a direct role in modification of the phenotype by position effect. Comparison of the rearrangement that have occurred during evolution and those detected in the human population shows a strong correlation for some of them...

Animals↗
PubMed1975

Procaryote phylogeny IV: concerning the phylogenetic status of a photosynthetic bacterium.

The 16S ribosomal RNA (30S subunit) of Rhodopseudomonas spheroides has been characterized in terms of T1 ribonuclease digestion products. This "fingerprint" ultimately permits the placement of R. spheroides into a detailed procaryotic phylogenetic tree. Given the number of major procaryotic lines that have been characterized in these terms to date, one can tentatively place the Athiorhodaceae closer to the Vibrio-Enteric group than to the Bacillaceae or Cyanophyta.

Base Sequence↗
PubMed1977

Evolutionary changes of alpha-crystallin and the phylogeny of mammalian orders.

The sequences of the A chains of the eye lens protein alpha-crystallin from seventeen mammalian species were compared. They showed a generally slow rate of evolution, but with marked variations in different lineages. Most substitutions have occurred in the C-terminal part of the chain, which probably forms part of the surface of the alpha-crystallin aggregate. The ancestral sequence method of Dayhoff revealed interesting indications about the phylogenetic relationships between the eleven mammalian orders that were represented by the investigated species. Most evident was the divergence of marsupial and placental orders. A notable resemblance between the hyrax and elephant sequences was observed, setting them apart from the ungulates, including whale. Primates, rodents, lagomorphs, insectivores and tupaiids seem to derive from a common stem group. These phylogenetic inferences are discussed in relation to current palaeontological and taxonomical opinions, and compared to evidence from other protein sequence data.

Amino Acid Sequence↗
PubMed1976

Congruency of phylogenies derived from different proteins. A molecular analysis of the phylogenetic position of cracid birds.

This communication examines the question of phylogenetic congruency--i.e., whether or not the branching order of evolutionary trees is independent of the protein studied. It was found that trees constructed for birds on the basis of immunological comparison of their transferrins, albumins, and ovalbumins agree approximately with a published tree based on the amino acid sequences of their lysozymes c. This congruency is especially noteworthy with respect to the phylogenetic position of the chachalaca, a Mexican bird classified on morphological grounds in the family Cracidae of the order Galliformes. At the protein level, this species differs as much from non-cracid galliform birds as does the duck, which belongs to another order. Despite the organismal similarity between cracid and non-cracid galliform birds, the molecular relationship is remote. If this contrast between organismal and molecular results had been based on comparative studies with only lysozyme, one could have ascribed the contrast to the possibility that chachalaca lysozyme was paralogous, rather than orthologous, to the other bird lysozymes c. Examination of several proteins is thus desirable in cases of possible paralogy.

Amino Acids↗
PubMed1978

Problems in the development of an explicit hypothetical phylogeny of the lower eukaryotes.

A semi-explicit arrangement of the lower eukaryotes is provided to serve as a basis for phyletic discussions. No single character is used to determine the position of all the groups. The tree provides no ready separation of protozoa, algae and fungi, groups assigned to these traditional assemblages being considered to be for the most part inextricably interwoven. Photosynthetic forms, whose relationships seem to be more readily discernable, are considered to have given rise repeatedly to nonphotosynthetic forms. The assumption that there are primitive "preflagellar" eukaryotes (red algae, non-flagellated fungi) is adopted. The potential value of mitochondrial features as indicators of broad affinities is emphasised, particularly in determining the probable affinities of non-photosynthetic forms, and this criterion is contra-indicative of a ciliate ancestry for the Metazoa. In the arrangement provided the distributions of chloroplast, mitochondrial and flagellar features match one another well, suggesting their probable co-evolution.

Animals↗
PubMed2025

A high-quality genomic catalog of the human oral microbiome broadens its phylogeny and clinical insights.

The oral microbiome is increasingly linked to human health. To further examine this microbial community, we present the human reference oral microbiome (HROM), with 72,641 high-quality genomes from 3,426 species, including 2,019 previously unidentified species, improving metagenomic sequence read classification over existing catalogs. Notably, HROM unveils 1,137 previously uncharacterized candidate phyla radiation (CPR) species, establishing Patescibacteria as the most prevalent phylum in the oral microbiota and distinct from environmental Patescibacteria. Additionally, an oral CPR subclade is associated with periodontitis, complementing Porphyromonas gingivalis in predicting disease. Finally, comparing HROM with reference genomes of the gut microbiome reveals taxonomic and functional divergence between these microbiomes. HROM contains 42 ectopic oral species, and their relative abundance in gut microbiota is predictive of intestinal, cardiovascular, and liver diseases. Thus, HROM offers an expanded view of the oral microbiome and highlights the clinical importance of further examining the links between oral microbes and systemic disorders.

Humans↗