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https://www.readbyqxmd.com/read/28922870/male-mutation-bias-is-the-main-force-shaping-chromosomal-substitution-rates-in-monotreme-mammals
#1
Vivian Link, Diana Aguilar-Gómez, Ciro Ramírez-Suástegui, Laurence D Hurst, Diego Cortez
In many species, spermatogenesis involves more cell divisions than oogenesis, and the male germline, therefore, accumulates more DNA replication errors, a phenomenon known as male mutation bias. The extent of male mutation bias (α) is estimated by comparing substitution rates of the X, Y, and autosomal chromosomes, as these chromosomes spend different proportions of their time in the germlines of the two sexes. Male mutation bias has been characterized in placental and marsupial mammals as well as birds, but analyses in monotremes failed to detect any such bias...
September 1, 2017: Genome Biology and Evolution
https://www.readbyqxmd.com/read/28919547/deep-sequencing-to-resolve-complex-diversity-of-apicomplexan-parasites-in-platypuses-and-echidnas-proof-of-principle-for-wildlife-disease-investigation
#2
Jan Šlapeta, Stefan Saverimuttu, Larry Vogelnest, Cheryl Sangster, Frances Hulst, Karrie Rose, Paul Thompson, Richard Whittington
The short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus) are iconic egg-laying monotremes (Mammalia: Monotremata) from Australasia. The aim of this study was to demonstrate the utility of diversity profiles in disease investigations of monotremes. Using small subunit (18S) rDNA amplicon deep-sequencing we demonstrated the presence of apicomplexan parasites and confirmed by direct and cloned amplicon gene sequencing Theileria ornithorhynchi, Theileria tachyglossi, Eimeria echidnae and Cryptosporidium fayeri...
September 12, 2017: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/28834173/conserved-and-variable-understanding-mammary-stem-cells-across-species
#3
REVIEW
Gat Rauner, Melissa M Ledet, Gerlinde R Van de Walle
Postnatal mammary gland development requires the presence of mammary stem and progenitor cells (MaSC), which give rise to functional milk-secreting cells and regenerate the mammary epithelium with each cycle of lactation. These long-lived, tissue-resident MaSC are also targets for malignant transformation and may be cancer cells-of-origin. Consequently, MaSC are extensively researched in relation to their role and function in development, tissue regeneration, lactation, and breast cancer. The basic structure and function of the mammary gland are conserved among all mammalian species, from the most primitive to the most evolved...
August 22, 2017: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
https://www.readbyqxmd.com/read/28792929/new-gliding-mammaliaforms-from-the-jurassic
#4
Qing-Jin Meng, David M Grossnickle, Di Liu, Yu-Guang Zhang, April I Neander, Qiang Ji, Zhe-Xi Luo
Stem mammaliaforms are Mesozoic forerunners to mammals, and they offer critical evidence for the anatomical evolution and ecological diversification during the earliest mammalian history. Two new eleutherodonts from the Late Jurassic period have skin membranes and skeletal features that are adapted for gliding. Characteristics of their digits provide evidence of roosting behaviour, as in dermopterans and bats, and their feet have a calcaneal calcar to support the uropagatium as in bats. The new volant taxa are phylogenetically nested with arboreal eleutherodonts...
August 17, 2017: Nature
https://www.readbyqxmd.com/read/28743766/the-evolution-of-duplicate-gene-expression-in-mammalian-organs
#5
Katerina Guschanski, Maria Warnefors, Henrik Kaessmann
Gene duplications generate genomic raw material that allows the emergence of novel functions, likely facilitating adaptive evolutionary innovations. However, global assessments of the functional and evolutionary relevance of duplicate genes in mammals were until recently limited by the lack of appropriate comparative data. Here, we report a large-scale study of the expression evolution of DNA-based functional gene duplicates in three major mammalian lineages (placental mammals, marsupials, egg-laying monotremes) and birds, on the basis of RNA sequencing (RNA-seq) data from nine species and eight organs...
September 2017: Genome Research
https://www.readbyqxmd.com/read/28683451/sleep-related-electrophysiology-and-behavior-of-tinamous-eudromia-elegans-tinamous-do-not-sleep-like-ostriches
#6
Ryan K Tisdale, Alexei L Vyssotski, John A Lesku, Niels C Rattenborg
The functions of slow wave sleep (SWS) and rapid eye movement (REM) sleep, distinct sleep substates present in both mammals and birds, remain unresolved. One approach to gaining insight into their function is to trace the evolution of these states through examining sleep in as many taxonomic groups as possible. The mammalian and avian clades are each composed of two extant groups, i.e., the monotremes (echidna and platypus) and therian (marsupial and eutherian [or placental]) mammals, and Palaeognaths (cassowaries, emus, kiwi, ostriches, rheas, and tinamous) and Neognaths (all other birds) among birds...
2017: Brain, Behavior and Evolution
https://www.readbyqxmd.com/read/28652620/differential-cohesin-loading-marks-paired-and-unpaired-regions-of-platypus-sex-chromosomes-at-prophase-i
#7
Aaron E Casey, Tasman J Daish, Jose Luis Barbero, Frank Grützner
Cohesins are vital for chromosome organisation during meiosis and mitosis. In addition to the important function in sister chromatid cohesion, these complexes play key roles in meiotic recombination, DSB repair, homologous chromosome pairing and segregation. Egg-laying mammals (monotremes) feature an unusually complex sex chromosome system, which raises fundamental questions about organisation and segregation during meiosis. We discovered a dynamic and differential accumulation of cohesins on sex chromosomes during platypus prophase I and specific reorganisation of the sex chromosome complex around a large nucleolar body...
June 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28620997/morphology-and-evolution-of-the-oral-shield-in-marsupial-neonates-including-the-newborn-monito-del-monte-dromiciops-gliroides-marsupialia-microbiotheria-pouch-young
#8
Nanette Y Schneider, Yamila Gurovich
Newborn marsupials can be arranged into three grades of developmental complexity based on their external form, as well as based on their organ systems and their cytology. The dasyurids are considered the least developed marsupials at birth, while didelphids and peramelids are intermediate, and macropods are the most developed. Currently there is still little information on caenolestid and microbiotherid development at birth. Developmental stages can be graded as G1, G2 and G3, with G1 being the least developed at birth, and G3 the most developed...
July 2017: Journal of Anatomy
https://www.readbyqxmd.com/read/28608500/morphological-and-molecular-evolution-of-the-ultimobranchial-gland-of-nonmammalian-vertebrates-with-special-reference-to-the-chicken-c-cells
#9
Yoko Kameda
This review summarizes the current understanding of the nonmammalian ultimobranchial gland from morphological and molecular perspectives. Ultimobranchial anlage of all animal species develops from the last pharyngeal pouch. The genes involved in the development of pharyngeal pouches are well conserved across vertebrates. The ultimobranchial anlage of nonmammalian vertebrates and monotremes does not merge with the thyroid, remaining as an independent organ throughout adulthood. Although C cells of all animal species secrete calcitonin, the shape, cellular components and location of the ultimobranchial gland vary from species to species...
June 12, 2017: Developmental Dynamics: An Official Publication of the American Association of Anatomists
https://www.readbyqxmd.com/read/28558801/astroglial-mediated-remodeling-of-the-interhemispheric-midline-during-telencephalic-development-is-exclusive-to-eutherian-mammals
#10
Ilan Gobius, Rodrigo Suárez, Laura Morcom, Annalisa Paolino, Timothy J Edwards, Peter Kozulin, Linda J Richards
The corpus callosum forms the major interhemispheric connection in the human brain and is unique to eutherian (or placental) mammals. The developmental events associated with the evolutionary emergence of this structure, however, remain poorly understood. A key step in callosal formation is the prior remodeling of the interhemispheric fissure by embryonic astroglial cells, which then subsequently act as a permissive substrate for callosal axons, enabling them to cross the interhemispheric midline. However, whether astroglial-mediated interhemispheric remodeling is unique to eutherian mammals, and thus possibly associated with the phylogenetic origin of the corpus callosum, or instead is a general feature of mammalian brain development, is not yet known...
May 30, 2017: Neural Development
https://www.readbyqxmd.com/read/28531897/magnetic-resonance-imaging-of-the-brain-of-a-monotreme-the-short-beaked-echidna-tachyglossus-aculeatus
#11
Sandilya Cherupalli, Craig D Hardman, Andre Bongers, Ken W S Ashwell
We used magnetic resonance imaging to study the anatomy of cortical regions, nuclear groups, and major tracts in the brain of a monotreme, i.e., the short-beaked echidna (Tachyglossus aculeatus). Our specimens were from a collection held at the Australian Museum in Sydney and had been stored in formaldehyde solution for at least 70 years. Despite this, we were able to detect fine detail in the nuclear divisions of structures as well as in fiber tracts. In particular, we could detect the medial lemniscus as it approached the ventral posterior thalamic nucleus, subdivisions within the ventral posterior thalamic nucleus, lamination and subdivisions within the hippocampal formation, components of the olfactory pathways, and nuclei within the temporal amygdala...
2017: Brain, Behavior and Evolution
https://www.readbyqxmd.com/read/28484364/energy-homeostasis-in-monotremes
#12
REVIEW
Stewart C Nicol
In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between "higher mammals" and "lower vertebrates." Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28429755/opossum-apobec1-is-a-dna-mutator-with-retrovirus-and-retroelement-restriction-activity
#13
Terumasa Ikeda, Mayuko Shimoda, Diako Ebrahimi, John L VandeBerg, Reuben S Harris, Atsushi Koito, Kazuhiko Maeda
APOBEC3s (A3s) are single-stranded DNA cytosine deaminases that provide innate immune defences against retroviruses and mobile elements. A3s are specific to eutherian mammals because no direct homologs exist at the syntenic genomic locus in metatherian (marsupial) or prototherian (monotreme) mammals. However, the A3s in these species have the likely evolutionary precursors, the antibody gene deaminase AID and the RNA/DNA editing enzyme APOBEC1 (A1). Here, we used cell culture-based assays to determine whether opossum A1 restricts the infectivity of retroviruses including human immunodeficiency virus type 1 (HIV-1) and the mobility of LTR/non-LTR retrotransposons...
April 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28344905/evolution-of-the-patellar-sesamoid-bone-in-mammals
#14
Mark E Samuels, Sophie Regnault, John R Hutchinson
The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable. Among extant (crown clade) groups it is found in most birds, most lizards, the monotreme mammals and almost all placental mammals, but it is absent in most marsupial mammals as well as many reptiles. Here, we integrate data from the literature and first-hand studies of fossil and recent skeletal remains to reconstruct the evolution of the mammalian patella...
2017: PeerJ
https://www.readbyqxmd.com/read/28326016/early-origin-and-evolution-of-the-angelman-syndrome-ubiquitin-ligase-gene-ube3a
#15
REVIEW
Masaaki Sato
The human Ube3a gene encodes an E3 ubiquitin ligase and exhibits brain-specific genomic imprinting. Genetic abnormalities that affect the maternal copy of this gene cause the neurodevelopmental disorder Angelman syndrome (AS), which is characterized by severe mental retardation, speech impairment, seizure, ataxia and some unique behavioral phenotypes. In this review article, I highlight the evolution of the Ube3a gene and its imprinting to provide evolutionary insights into AS. Recent comparative genomic studies have revealed that Ube3a is most phylogenetically similar to HECTD2 among the human HECT (homologous to the E6AP carboxyl terminus) family of E3 ubiquitin ligases, and its distant evolutionary origin can be traced to common ancestors of fungi and animals...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28132863/immune-endocrine-interactions-in-marsupials-and-monotremes
#16
REVIEW
E Peel, K Belov
Interactions between the immune and endocrine systems are not well studied in marsupials and monotremes. One exception to this is the phenomenon of semelparity, which is well covered in the literature as this is an unusual reproductive strategy amongst mammals and is only observed in some dasyurid and didelphid marsupials. Thymus involution provides a direct link between the endocrine and immune systems and warrants further study in marsupials and monotremes. The thymus is a primary immune tissue which is essential for overall immune function...
April 1, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28007525/the-mammalian-cretaceous-cochlear-revolution
#17
REVIEW
Geoffrey A Manley
The hearing organs of amniote vertebrates show large differences in their size and structure between the species' groups. In spite of this, their performance in terms of hearing sensitivity and the frequency selectivity of auditory-nerve units shows unexpectedly small differences. The only substantial difference is that therian, defined as live-bearing, mammalian groups are able to hear ultrasonic frequencies (above 15-20 kHz), whereas in contrast monotreme (egg laying) mammals and all non-mammalian amniotes cannot...
December 19, 2016: Hearing Research
https://www.readbyqxmd.com/read/27898108/monotreme-glucagon-like-peptide-1-in-venom-and-gut-one-gene-two-very-different-functions
#18
Enkhjargal Tsend-Ayush, Chuan He, Mark A Myers, Sof Andrikopoulos, Nicole Wong, Patrick M Sexton, Denise Wootten, Briony E Forbes, Frank Grutzner
The importance of Glucagon like peptide 1 (GLP-1) for metabolic control and insulin release sparked the evolution of genes mimicking GLP-1 action in venomous species (e.g. Exendin-4 in Heloderma suspectum (gila monster)). We discovered that platypus and echidna express a single GLP-1 peptide in both intestine and venom. Specific changes in GLP-1 of monotreme mammals result in resistance to DPP-4 cleavage which is also observed in the GLP-1 like Exendin-4 expressed in Heloderma venom. Remarkably we discovered that monotremes evolved an alternative mechanism to degrade GLP-1...
November 29, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27889918/inner-ear-labyrinth-anatomy-of-monotremes-and-implications-for-mammalian-inner-ear-evolution
#19
Julia A Schultz, Ulrich Zeller, Zhe-Xi Luo
The monophyletic clade Monotremata branches early from the rest of the mammalian crown group in the Jurassic and members of this clade retain many ancestral mammalian traits. Thus, accurate and detailed anatomical descriptions of this group can offer unique insight into the early evolutionary history of Mammalia. In this study, we examine the inner ear anatomy of two extant monotremes, Ornithorhynchus anatinus and Tachyglossus aculeatus, with the primary goals of elucidating the ancestral mammalian ear morphology and resolving inconsistencies found within previous descriptive literature...
February 2017: Journal of Morphology
https://www.readbyqxmd.com/read/27825298/the-ut-family-of-mhc-class-i-loci-unique-to-non-eutherian-mammals-has-limited-polymorphism-and-tissue-specific-patterns-of-expression-in-the-opossum
#20
Katina V Krasnec, Anthony T Papenfuss, Robert D Miller
BACKGROUND: The Major Histocompatibility Complex (MHC) class I family of genes encode for molecules that have well-conserved structures, but have evolved to perform diverse functions. The availability of the gray, short-tailed opossum, Monodelphis domestica whole genome sequence has allowed for analysis of MHC class I gene content in this marsupial. Utilization of a novel method to search for MHC related domain structures revealed a previously unknown family of MHC class I-related genes...
November 8, 2016: BMC Immunology
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