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From fish to modern humans – comparative anatomy, homologies and evolution of the head and neck musculature

Diogo, R; Abdala, V; Lonergan, N; Wood, B A
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
16.43%
In a recent paper Diogo (2008) reported the results of the first part of an investigation of the comparative anatomy, homologies and evolution of the head and neck muscles of osteichthyans (bony fish + tetrapods). That report mainly focused on actinopterygian fish, but also compared these fish with certain non-mammalian sarcopterygians. The present paper focuses mainly on sarcopterygians, and particularly on how the head and neck muscles have evolved during the transitions from sarcopterygian fish and non-mammalian tetrapods to monotreme and therian mammals, including modern humans. The data obtained from our dissections of the head and neck muscles of representative members of sarcopterygian fish, amphibians, reptiles, monotremes and therian mammals, such as rodents, tree-shrews, colugos and primates, including modern humans, are compared with the information available in the literature. Our observations and comparisons indicate that the number of mandibular and true branchial muscles (sensu this work) present in modern humans is smaller than that found in mammals such as tree-shrews, rats and monotremes, as well as in reptiles such as lizards. Regarding the pharyngeal musculature, there is an increase in the number of muscles at the time of the evolutionary transition leading to therian mammals...

Those other mammals: The immunoglobulins and T cell receptors of marsupials and monotremes

Miller, Robert D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.14%
This review summarizes analyses of marsupial and monotreme immunoglobulin and T cell receptor genetics and expression published over the past decade. Analyses of recently completed whole genome sequences from the opossum and the platypus have yielded insight into the evolution of the common antigen receptor systems, as well as discovery of novel receptors that appear to have been lost in eutherian mammals. These species are also useful for investigation of the development of the immune system in organisms notable for giving birth to highly altricial young, as well as the evolution of maternal immunity through comparison of oviparous and viviparous mammals.

A Comparative Approach to Understanding Tissue-Specific Expression of Uncoupling Protein 1 Expression in Adipose Tissue

Shore, Andrew; Emes, Richard D.; Wessely, Frank; Kemp, Paul; Cillo, Clemente; D’Armiento, Maria; Hoggard, Nigel; Lomax, Michael A.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 03/01/2013 EN
Relevância na Pesquisa
26.14%
The thermoregulatory function of brown adipose tissue (BAT) is due to the tissue-specific expression of uncoupling protein 1 (UCP1) which is thought to have evolved in early mammals. We report that a CpG island close to the UCP1 transcription start site is highly conserved in all 29 vertebrates examined apart from the mouse and xenopus. Using methylation sensitive restriction digest and bisulfite mapping we show that the CpG island in both the bovine and human is largely un-methylated and is not related to differences in UCP1 expression between white and BAT. Tissue-specific expression of UCP1 has been proposed to be regulated by a conserved 5′ distal enhancer which has been reported to be absent in marsupials. We demonstrate that the enhancer, is also absent in five eutherians as well as marsupials, monotremes, amphibians, and fish, is present in pigs despite UCP1 having become a pseudogene, and that absence of the enhancer element does not relate to BAT-specific UCP1 expression. We identify an additional putative 5′ regulatory unit which is conserved in 14 eutherian species but absent in other eutherians and vertebrates, but again unrelated to UCP1 expression. We conclude that despite clear evidence of conservation of regulatory elements in the UCP1 5′ untranslated region...

Molecular biology and evolution of beta-globin genes in monotremes / Mi-Hye Lee.; Molecular biology and evolution of beta-globin genese in monotremes

Lee, Mi-Hye
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 93916 bytes; application/pdf
Publicado em //1997 EN
Relevância na Pesquisa
46.72%
The evolutionary relationships of the beta-like globin genes were studied by applying maximum parsimony methods to aligned DNA sequences.; Thesis (Ph.D.)--University of Adelaide, Dept. of Genetics, 1998?; Erratum pasted on front fly-leaf.; Bibliography: leaves 180-202.; xvii, 220 leaves : ill. (some col.) ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

The monotreme genome: a patchwork of reptile mammal and unique features?

Grutzner, F.; Deakin, J.; Rens, W.; El-Mogharbel, N.; Marshall Graves, J.
Fonte: Elsevier Science Inc Publicador: Elsevier Science Inc
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
Relevância na Pesquisa
26.58%
The first specimen of platypus (Ornithorhynchus anatinus) that reached Britain in the late 18th century was regarded a scientific hoax. Over decades the anatomical characteristics of these unique mammals, such as egg laying and the existence of mammary glands, were hotly debated before they were accepted. Within the last 40 years, more and more details of monotreme physiology, histology, reproduction and genetics have been revealed. Some show similarities with birds or reptiles, some with therian mammals, but many are very specific to monotremes. The genome is no exception to monotreme uniqueness. An early opinion was that the karyotype, composed of a few large chromosomes and many small ones, resembled bird and reptile macro- and micro-chromosomes. However, the platypus genome also features characteristics that are not present in other mammals, such as a complex translocation system. The sex chromosome system is still not resolved. Nothing is known about dosage compensation and, unlike in therian mammals, there seems to be no genomic imprinting. In this article we will recount the mysteries of the monotreme genome and describe how we are using recently developed technology to identify chromosomes in mitosis, meiosis and sperm, to map genes to chromosomes...

The multiple sex chromosomes of platypus and echidna are not completely identical and several share homology with the avian Z

Rens, W.; O'Brien, P.; Grutzner, F.; Clarke, O.; Graphodatskaya, D.; Tsend-Ayush, E.; Trifonov, V.; Skelton, H.; Wallis, M.; Johnston, S.; Veyrunes, F.; Graves, J.; Ferguson-Smith, M.
Fonte: BioMed Central Ltd. Publicador: BioMed Central Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2007 EN
Relevância na Pesquisa
26.43%
Background: Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping. Results: Chromosome painting reveals a meiotic chain of nine sex chromosomes in the male echidna and establishes their order in the chain. Two of those differ from those in the platypus, three of the platypus sex chromosomes differ from those of the echidna and the order of several chromosomes is rearranged. Comparative gene mapping shows that, in addition to bird autosome regions, regions of bird Z chromosomes are homologous to regions in four platypus X chromosomes, that is, X1, X2, X3, X5, and in chromosome Y1. Conclusion: Monotreme sex chromosomes are easiest to explain on the hypothesis that autosomes were added sequentially to the translocation chain...

The monotreme genome: A patchwork of reptile, mammal and unique features

Gruetzner, Frank; Deakin, Janine; Rens, Willem; El-Mogharbel, Nisrine; Graves, Jennifer
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.58%
The first specimen of platypus (Ornithorhynchus anatinus) that reached Britain in the late 18th century was regarded a scientific hoax. Over decades the anatomical characteristics of these unique mammals, such as egg laying and the existence of mammary glands, were hotly debated before they were accepted. Within the last 40 years, more and more details of monotreme physiology, histology, reproduction and genetics have been revealed. Some show similarities with birds or reptiles, some with therian mammals, but many are very specific to monotremes. The genome is no exception to monotreme uniqueness. An early opinion was that the karyotype, composed of a few large chromosomes and many small ones, resembled bird and reptile macro- and micro-chromosomes. However, the platypus genome also features characteristics that are not present in other mammals, such as a complex translocation system. The sex chromosome system is still not resolved. Nothing is known about dosage compensation and, unlike in therian mammals, there seems to be no genomic imprinting. In this article we will recount the mysteries of the monotreme genome and describe how we are using recently developed technology to identify chromosomes in mitosis, meiosis and sperm, to map genes to chromosomes...

Sex chromosomes and sex determination in weird mammals

Graves, Jennifer
Fonte: S Karger AG Publicador: S Karger AG
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.14%
Weird mammals are of two types. Highly divergent mammals, such as the marsupials and monotremes, have informed us of the evolutionary history of the Y chromosome and sex-determining gene, and the recently specialized rodents can help us predict its future. The Y chromosome has had a short but eventful history, and is already heading briskly for oblivion. It originated as a homologous partner of the X when it acquired a sex-determining gene (not necessarily SRY). Most of the genes on the Y, even those with a male-specific function, evolved from genes now on the X. At the mercy of a high rate of variability and the forces of drift and selection, the Y has lost genes at a rate of 3-6 genes/million years, sparing those that acquired critical male-specific functions. Even these genes have disappeared from one mammalian lineage or another as their functions were usurped by genes elsewhere in the genome. The mammalian testis-determining gene, SRY, is a typical Y-borne gene. It arose by truncation of a gene (SOX3) on the X that is expressed in brain development, and it may work by interacting with (inhibiting?) related genes, including SOX9. Variant sex-determining systems in rodents show that the action of SRY can change, as it evidently has in the mouse...