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Antoine Molaro, Janet M Young, Harmit S Malik
Eukaryotic genomes must accomplish both compact packaging for genome stability and inheritance, as well as accessibility for gene expression. They do so using post-translational modifications of four ancient canonical histone proteins (H2A, H2B, H3, and H4) and by deploying histone variants with specialized chromatin functions. Some histone variants are conserved across all eukaryotes, whereas others are lineage-specific. Here, we performed detailed phylogenomic analyses of "short H2A histone" variants found in mammalian genomes...
March 16, 2018: Genome Research
Ken W S Ashwell, Boaz Shulruf
We have used an unbiased statistical approach to compare the pace of development in the main and accessory olfactory systems in monotremes and metatherians with that in rodents and humans. We hypothesized that if metatherians and monotremes, which are born at small body size, use olfaction to locate the pouch and/or teat/milk field, then olfactory structures should reach structural maturity in metatherians and monotremes at a smaller size than eutherians like humans and rodents. The achievement of key structural milestones in the development of the main and accessory olfactory systems (11 and 7 milestones, respectively) was scored for 354 specimens and compared against a measure of general somatic growth (body length)...
March 15, 2018: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
Gráinne I McNamara, Rosalind M John, Anthony R Isles
Genomic imprinting, the epigenetic process by which transcription occurs from a single parental allele, is believed to influence social behaviors in mammals. An important social behavior is group living, which is enriched in Eutherian mammals relative to monotremes and marsupials. Group living facilitates resource acquisition, defense of territory and co-care of young, but requires a stable social group with complex inter-individual relationships. Co-occurring with increased group living in Eutherians is an increase in the number of imprinted loci, including that spanning the maternally expressed Cdkn1c ...
2018: Frontiers in Behavioral Neuroscience
Célia Gautier, Sophie-Penelope Guenin, Isabelle Riest-Fery, Tahlia Jade Perry, Céline Legros, Olivier Nosjean, Valerie Simonneaux, Frank Grützner, Jean A Boutin
Melatonin is a neurohormone produced in both animals and plants. It binds at least three G-protein-coupled receptors: MT1 and MT2, and Mel1cGPR. Mammalian GPR50 evolved from the reptilian/avian Mel1c and lost its capacity to bind melatonin in all the therian mammal species that have been tested. In order to determine if binding is lost in the oldest surviving mammalian lineage of monotremes we investigated whether the melatonin receptor has the ability to bind melatonin in the platypus (Ornithorhynchus anatinus), and evaluated its pharmacological profile...
2018: PloS One
Lorenzo Alibardi
The presence and localization of cystatin, a cysteine protease inhibitor involved in barrier formation in human and mice epidermis, has been studied in the epidermis of piscine and terrestrial vertebrates using a mouse monoclonal antibody. Cystatin has been localized by Immunostaining in the pre-corneous and corneous layers of monotreme, marsupial and placental mammals, and sparsely in the thin corneous layer of birds. Cystatin-immunolabeling is present in the pre-corneous and corneous layer of crocodilian and turtle epidermis, in the alpha-corneous layer and likely also in the beta-corneous layer of the epidermis in lizards, snakes and the tuatara...
February 13, 2018: Zoology: Analysis of Complex Systems, ZACS
Stephen Frankenberg
Marsupials and monotremes differ from eutherian mammals in many features of their reproduction and development. Some features appear to be representative of transitional stages in evolution from therapsid reptiles to humans and mice, particularly with respect to the extraembryonic tissues that have undergone remarkable modifications to accommodate reduced egg size and quantity of yolk/deutoplasm, and increasing emphasis on viviparity and placentation. Trophoblast and hypoblast contribute the epithelial layers in most of the extraembryonic membranes and are the first two lineages to differentiate from the embryonic lineage...
2018: Current Topics in Developmental Biology
Janet Newman, Julie A Sharp, Ashwantha Kumar Enjapoori, John Bentley, Kevin R Nicholas, Timothy E Adams, Thomas S Peat
Monotreme lactation protein (MLP) is a recently identified protein with antimicrobial activity. It is present in the milk of monotremes and is unique to this lineage. To characterize MLP and to gain insight into the potential role of this protein in the evolution of lactation, the crystal structure of duck-billed platypus (Ornithorhynchus anatinus) MLP was determined at 1.82 Å resolution. This is the first structure to be reported for this novel, mammalian antibacterial protein. MLP was expressed as a FLAG epitope-tagged protein in mammalian cells and crystallized readily, with at least three space groups being observed (P1, C2 and P21)...
January 1, 2018: Acta Crystallographica. Section F, Structural Biology Communications
T Gazoni, C F B Haddad, H Narimatsu, D C Cabral-de-Mello, M L Lyra, P P Parise-Maltempi
Heteromorphic sex chromosomes are common in eukaryotes and largely ubiquitous in birds and mammals. The largest number of multiple sex chromosomes in vertebrates known today is found in the monotreme platypus (Ornithorhynchus anatinus, 2n = 52) which exhibits precisely 10 sex chromosomes. Interestingly, fish, amphibians, and reptiles have sex determination mechanisms that do or do not involve morphologically differentiated sex chromosomes. Relatively few amphibian species carry heteromorphic sex chromosomes, and when present, they are frequently represented by only one pair, either XX:XY or ZZ:ZW types...
January 26, 2018: Chromosoma
Brooke Storey-Lewis, Ann Mitrovic, Brent McParland
Babesia and Theileria are intraerythrocytic protozoans of the phylum Apicomplexa. These species are capable of infecting wild and domestic animals and have historically caused great economic loss in the agricultural industry. In recent years human babesiosis has been deemed an emerging zoonosis in North America, Europe and Asia. The first locally acquired case of babesiosis in Australia, caused by Babesia microti, was reported in March 2012. A number of native Babesia and Theileria species have been identified in Australian marsupials, however their associated tick vectors and threat to human health is unknown...
December 24, 2017: Ticks and Tick-borne Diseases
Patrick Arnold, Borja Esteve-Altava, Martin S Fischer
BACKGROUND: The increase in locomotor and metabolic performance during mammalian evolution was accompanied by the limitation of the number of cervical vertebrae to only seven. In turn, nuchal muscles underwent a reorganization while forelimb muscles expanded into the neck region. As variation in the cervical spine is low, the variation in the arrangement of the neck muscles and their attachment sites (i.e., the variability of the neck's musculoskeletal organization) is thus proposed to be an important source of neck disparity across mammals...
December 13, 2017: BMC Evolutionary Biology
Cheryl S Rosenfeld
Brain sexual differentiation is orchestrated by precise coordination of sex steroid hormones. In some species, programming of select male brain regions is dependent upon aromatization of testosterone to estrogen. In mammals, these hormones surge during the organizational and activational periods that occur during perinatal development and adulthood, respectively. In various fish and reptiles, incubation temperature during a critical embryonic period results in male or female sexual differentiation, but this can be overridden in males by early exposure to estrogenic chemicals...
2017: Frontiers in Neuroscience
Gang Han, Fangyuan Mao, Shundong Bi, Yuanqing Wang, Jin Meng
Gliding is a distinctive locomotion type that has been identified in only three mammal species from the Mesozoic era. Here we describe another Jurassic glider that belongs to the euharamiyidan mammals and shows hair details on its gliding membrane that are highly similar to those of extant gliding mammals. This species possesses a five-boned auditory apparatus consisting of the stapes, incus, malleus, ectotympanic and surangular, representing, to our knowledge, the earliest known definitive mammalian middle ear...
November 23, 2017: Nature
Michael J Gaudry, Kevin L Campbell
Uncoupling protein 1 (UCP1) permits non-shivering thermogenesis (NST) when highly expressed in brown adipose tissue (BAT) mitochondria. Exclusive to placental mammals, BAT has commonly been regarded to be advantageous for thermoregulation in hibernators, small-bodied species, and the neonates of larger species. While numerous regulatory control motifs associated with UCP1 transcription have been proposed for murid rodents, it remains unclear whether these are conserved across the eutherian mammal phylogeny and hence essential for UCP1 expression...
2017: Frontiers in Physiology
Kirsten Ferner, Julia A Schultz, Ulrich Zeller
The existing different modes of reproduction in monotremes, marsupials and placentals are the main source for our current understanding of the origin and evolution of the mammalian reproduction. The reproductive strategies and, in particular, the maturity states of the neonates differ remarkably between the three groups. Monotremes, for example, are the only extant mammals that lay eggs and incubate them for the last third of their embryonic development. In contrast, marsupials and placentals are viviparous and rely on intra-uterine development of the neonates via choriovitelline (mainly marsupials) and chorioallantoic (mainly placentals) placentae...
December 2017: Journal of Anatomy
Emma Peel, Yuanyuan Cheng, Julianne T Djordjevic, Michael Kuhn, Tania Sorrell, Katherine Belov
With the growing demand for new antibiotics to combat increasing multi-drug resistance, a family of antimicrobial peptides known as cathelicidins has emerged as potential candidates. Expansions in cathelicidin-encoding genes in marsupials and monotremes are of specific interest as the peptides they encode have evolved to protect immunologically naive young in the harsh conditions of the pouch and burrow. Our previous work demonstrated that some marsupial and monotreme cathelicidins have broad-spectrum antibacterial activity and kill resistant bacteria, but the activity of many cathelicidins is unknown...
September 27, 2017: Microbiology
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
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 13, 2017: Infection, Genetics and Evolution
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
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
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
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