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Sex evolution

M P Machado, I Matos, A R Grosso, M Schartl, M M Coelho
Sex determination is a highly variable process that utilizes many different mechanisms to initiate the cascade of differentiation processes. The molecular pathways controlling sexual development are less conserved than previously assumed, and appear to require active maintenance in some species; indeed, the developmental decision of gonad phenotype in gonochoristic species is not fixed at an early developmental stage. Much of the knowledge about sex determination mechanisms was derived from research on gonochoristic, non-seasonal breeders...
October 22, 2016: Molecular Reproduction and Development
Sandra A Heldstab, Carel P van Schaik, Karin Isler
Humans stand out among non-aquatic mammals by having both an extremely large brain and a relatively large amount of body fat. To understand the evolution of this human peculiarity we report a phylogenetic comparative study of 120 mammalian species, including 30 primates, using seasonal variation in adult body mass as a proxy of the tendency to store fat. Species that rely on storing fat to survive lean periods are expected to be less active because of higher costs of locomotion and have increased predation risk due to reduced agility...
November 2016: Journal of Human Evolution
Vanessa Bellini Bardella, Sebastián Pita, André Luis Laforga Vanzela, Cleber Galvão, Francisco Panzera
The subfamily Triatominae (Hemiptera, Reduviidae) includes 150 species of blood-sucking insects, vectors of Chagas disease or American trypanosomiasis. Karyotypic information reveals a striking stability in the number of autosomes. However, this group shows substantial variability in genome size, the amount and distribution of C-heterochromatin, and the chromosome positions of 45S rDNA clusters. Here, we analysed the karyotypes of 41 species from six different genera with C-fluorescence banding in order to evaluate the base-pair richness of heterochromatic regions...
October 2016: Memórias do Instituto Oswaldo Cruz
William J Gammerdinger, Matthew A Conte, Jean-François Baroiller, Helena D'Cotta, Thomas D Kocher
BACKGROUND: Inversions and other structural polymorphisms often reduce the rate of recombination between sex chromosomes, making it impossible to fine map sex-determination loci using traditional genetic mapping techniques. Here we compare distantly related species of tilapia that each segregate an XY system of sex-determination on linkage group 1. We use whole genome sequencing to identify shared sex-patterned polymorphisms, which are candidates for the ancestral sex-determination mutation...
October 18, 2016: BMC Genomics
Martha S Hunter, Peter Asiimwe, Anna G Himler, Suzanne E Kelly
Arthropods commonly carry maternally-inherited intracellular bacterial symbionts that may profoundly influence host biology and evolution. The intracellular symbiont Rickettsia sp. nr. bellii swept rapidly into populations of the sweetpotato whitefly Bemisia tabaci in the southwestern USA. Previous laboratory experiments showed female-bias and fitness benefits were associated with Rickettsia infection, potentially explaining the high frequencies of infection observed in field populations, but the effects varied with whitefly genetic line...
October 17, 2016: Journal of Evolutionary Biology
Masahito Tsuboi, Adam Chee Ooi Lim, Boon Leong Ooi, Mei Yee Yip, Ving Ching Chong, Ingrid Ahnesjö, Niclas Kolm
Brain size varies greatly at all taxonomic levels. Feeding ecology, life history and sexual selection have been proposed as key components in generating contemporary diversity in brain size across vertebrates. Analyses of brain size evolution have, however, been limited to lineages where males predominantly compete for mating and females choose mates. Here, we present the first original data set of brain sizes in pipefishes and seahorses (Syngnathidae) a group in which intense female mating competition occurs in many species...
October 17, 2016: Journal of Evolutionary Biology
Liandong Yang, Zhaolei Zhang, Shunping He
Males and females often display extensive phenotypic differences, and many of these sexual dimorphisms are thought to result from differences between males and females in expression of genes present in both sexes. Sex-biased genes have been shown to exhibit accelerated rates of evolution in a wide array of species, however the cause of this remains enigmatic. In this study, we investigate the extent and evolutionary dynamics of sex-biased gene expression in zebrafish. Our results indicate that both male-biased genes and female-biased genes exhibit accelerated evolution at the protein level...
October 13, 2016: Genome Biology and Evolution
Venkatesh L Murthy, Siddique A Abbasi, Juned Siddique, Laura A Colangelo, Jared Reis, Bharath A Venkatesh, J Jeffrey Carr, James G Terry, Sarah M Camhi, Michael Jerosch-Herold, Sarah de Ferranti, Saumya Das, Jane Freedman, Mercedes R Carnethon, Cora E Lewis, Joao A C Lima, Ravi V Shah
BACKGROUND: Despite evidence suggesting that early metabolic dysfunction impacts cardiovascular disease risk, current guidelines focus on risk assessments later in life, missing early transitions in metabolic risk that may represent opportunities for averting the development of cardiovascular disease. METHODS AND RESULTS: In 4420 young adults in the Coronary Artery Risk Development in Young Adults (CARDIA) study, we defined a "metabolic" risk score based on components of the Third Report of the Adult Treatment Panel's definition of metabolic syndrome...
October 13, 2016: Journal of the American Heart Association
Mitzi I Kuroda, Andres Hilfiker, John C Lucchesi
The sex chromosomes have special significance in the history of genetics. The chromosomal basis of inheritance was firmly established when Calvin Bridges demonstrated that exceptions to Mendel's laws of segregation were accompanied at the cytological level by exceptional sex chromosome segregation. The morphological differences between X and Y exploited in Bridges' experiments arose as a consequence of the evolution of the sex chromosomes. Originally a homologous chromosome pair, the degeneration of the Y chromosome has been accompanied by a requirement for increased expression of the single X chromosome in males...
October 2016: Genetics
Philippe Bousquet, Hélène Ansermino, Pierre Canal, Matthieu Renaud, Christèle Artz
Using implant to replace a tooth is a well known treatment. However, the practitioner must keep in mind that osteointegrated implants behave like ankylosed teeth, and their evolution does not follow the alveolar processes of the adjacent teeth during growth. This growth decreases after 20 years, but remains present. This can lead to infraposition functionally and aesthetically failure for the implant therapy. Risk factors, like patient's age, sex and shape of the face must be evaluated. Most palatal implant positioning and use of screwed prosthetic tooth can permit the infraposition treatment during years of aging...
September 2016: L' Orthodontie Française
Dominique Castex, Sacha Kacki
The analysis of biological parameters such as age and sex is particularly relevant to the interpretation of ancient skeletal assemblages related to abrupt mortality crises, and more particularly epidemics. In such a context, the mechanisms of selection within a population or part of a population differ according to the pathogen involved. They may also vary depending on the period and location in which the population lived. Here, we illustrate the specificity of plague mortality through the study of several European burial sites contemporary with the first and second plague pandemics...
August 2016: Microbiology Spectrum
François Olivier, Sophie Nadeau, Georges Caouette, Bruno Piedboeuf
BACKGROUND: Late preterm infants (34-36 weeks' gestation) remain a population at risk for apnea of prematurity (AOP). As infants affected by respiratory distress syndrome (RDS) have immature lungs, they might also have immature control of breathing. Our hypothesis is that an association exists between RDS and AOP in late preterm infants. OBJECTIVE: The primary objective of this study was to assess the association between RDS and AOP in late preterm infants. The secondary objective was to evaluate if an association exists between apparent RDS severity and AOP...
2016: Frontiers in Pediatrics
Hanna Koch, Lutz Becks
A species reproductive mode, along with its associated costs and benefits, can play a significant role in its evolution and survival. Facultative sexuality, being able to reproduce both sexually and asexually, has been deemed evolutionary favourable as the benefits of either mode may be fully realized. In fact, many studies have focused on identifying the benefits of sex and/or the forces selecting for increased rates of sex using facultative sexual species. The costs of either mode however can also have a profound impact on a population's evolutionary trajectory...
October 7, 2016: Journal of Evolutionary Biology
Zofia M Sikorska-Piwowska, Antoni L Dawidowicz
The authors examined a large random sample of skulls from two species of macaques: rhesus monkeys and cynomolgus monkeys. The skulls were measured, divided into age and sex groups and thoroughly analysed using statistical methods. The analysis shows that skulls of young rhesuses are considerably more domed, i.e. have better-developed neurocrania, than their adult counterparts. Male and female skulls, on the other hand, were found to be very similar, which means that sexual dimorphism of the rhesus macaque was suppressed...
October 7, 2016: Folia Morphologica (Warsz)
Hong Wu, Yan-Hu Liu, Guo-Dong Wang, Chun-Tao Yang, Newton O Otecko, Fei Liu, Shi-Fang Wu, Lu Wang, Li Yu, Ya-Ping Zhang
Genome-wide studies on high-altitude adaptation have received increased attention as a classical case of organismal evolution under extreme environment. However, the current genetic understanding of high-altitude adaptation emanated mainly from autosomal analyses. Only a few earlier genomic studies paid attention to the allosome. In this study, we performed an intensive scan of the X chromosome of public genomic data generated from Tibetan Mastiff (TM) and five other dog populations for indications of high-altitude adaptation...
October 7, 2016: Scientific Reports
Petr Ráb, Cassia F Yano, Sébastien Lavoué, Oladele I Jegede, Luiz A C Bertollo, Tariq Ezaz, Zuzana Majtánová, Ezequiel A de Oliveira, Marcelo B Cioffi
The monophyletic order Osteoglossiformes represents one of the most ancestral groups of teleosts and has at least 1 representative in all continents of the southern hemisphere, with the exception of Antarctica. However, despite its phylogenetic and biogeographical importance, cytogenetic data in Osteoglossiformes are scarce. Here, karyotype and chromosomal characteristics of the lower Niger River population of the African butterfly fish Pantodon buchholzi, the sole species of the family Pantodontidae (Osteoglossiformes), were examined using conventional and molecular cytogenetic approaches...
October 7, 2016: Cytogenetic and Genome Research
Wei Yin, Zong-Ji Wang, Qi-Ye Li, Jin-Ming Lian, Yang Zhou, Bing-Zheng Lu, Li-Jun Jin, Peng-Xin Qiu, Pei Zhang, Wen-Bo Zhu, Bo Wen, Yi-Jun Huang, Zhi-Long Lin, Bi-Tao Qiu, Xing-Wen Su, Huan-Ming Yang, Guo-Jie Zhang, Guang-Mei Yan, Qi Zhou
Snakes have numerous features distinctive from other tetrapods and a rich history of genome evolution that is still obscure. Here, we report the high-quality genome of the five-pacer viper, Deinagkistrodon acutus, and comparative analyses with other representative snake and lizard genomes. We map the evolutionary trajectories of transposable elements (TEs), developmental genes and sex chromosomes onto the snake phylogeny. TEs exhibit dynamic lineage-specific expansion, and many viper TEs show brain-specific gene expression along with their nearby genes...
October 6, 2016: Nature Communications
Martin Franke, Daniel M Ibrahim, Guillaume Andrey, Wibke Schwarzer, Verena Heinrich, Robert Schöpflin, Katerina Kraft, Rieke Kempfer, Ivana Jerković, Wing-Lee Chan, Malte Spielmann, Bernd Timmermann, Lars Wittler, Ingo Kurth, Paola Cambiaso, Orsetta Zuffardi, Gunnar Houge, Lindsay Lambie, Francesco Brancati, Ana Pombo, Martin Vingron, Francois Spitz, Stefan Mundlos
Chromosome conformation capture methods have identified subchromosomal structures of higher-order chromatin interactions called topologically associated domains (TADs) that are separated from each other by boundary regions. By subdividing the genome into discrete regulatory units, TADs restrict the contacts that enhancers establish with their target genes. However, the mechanisms that underlie partitioning of the genome into TADs remain poorly understood. Here we show by chromosome conformation capture (capture Hi-C and 4C-seq methods) that genomic duplications in patient cells and genetically modified mice can result in the formation of new chromatin domains (neo-TADs) and that this process determines their molecular pathology...
October 5, 2016: Nature
Joachim Ruther, Åsa K Hagström, Birgit Brandstetter, John Hofferberth, Astrid Bruckmann, Florian Semmelmann, Michaela Fink, Helena Lowack, Sabine Laberer, Oliver Niehuis, Rainer Deutzmann, Christer Löfstedt, Reinhard Sterner
Males of all species of the parasitic wasp genus Nasonia use (4R,5S)-5-hydroxy-4-decanolide (RS) as component of their sex pheromone while only N. vitripennis (Nv), employs additionally (4R,5R)-5-hydroxy-4-decanolide (RR). Three genes coding for the NAD(+)-dependent short-chain dehydrogenases/reductases (SDRs) NV10127, NV10128, and NV10129 are linked to the ability of Nv to produce RR. Here we show by assaying recombinant enzymes that SDRs from both Nv and N. giraulti (Ng), the latter a species with only RS in the pheromone, epimerise RS into RR and vice versa with (4R)-5-oxo-4-decanolide as an intermediate...
October 5, 2016: Scientific Reports
Fotini A Koutroumpa, Astrid T Groot, Teun Dekker, David G Heckel
The sexual pheromone communication system of moths is a model system for studies of the evolution of reproductive isolation. Females emit a blend of volatile components that males detect at a distance. Species differences in female pheromone composition and male response directly reinforce reproductive isolation in nature, because even slight variations in the species-specific pheromone blend are usually rejected by the male. The mechanisms by which a new pheromone signal-response system could evolve are enigmatic, because any deviation from the optimally attractive blend should be selected against...
October 3, 2016: Proceedings of the National Academy of Sciences of the United States of America
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