Chimerism in Wild Adult Populations of the Broadcast Spawning Coral Acropora millepora on the Great Barrier Reef

Chimeras are organisms containing tissues or cells of two or more genetically distinct individuals, and are known to exist in at least nine phyla of protists, plants, and animals. Although widespread and common in marine invertebrates, the extent of chimerism in wild populations of reef corals is unknown.The extent of chimerism was explored within two populations of a common coral, Acropora millepora, on the Great Barrier Reef, Australia, by using up to 12 polymorphic DNA microsatellite loci. At least 2% and 5% of Magnetic Island and Pelorus Island populations of A. millepora, respectively, were found to be chimeras (3% overall), based on conservative estimates. A slightly less conservative estimate indicated that 5% of colonies in each population were chimeras. These values are likely to be vast underestimates of the true extent of chimerism, as our sampling protocol was restricted to a maximum of eight branches per colony, while most colonies consist of hundreds of branches. Genotypes within chimeric corals showed high relatedness, indicating that genetic similarity is a prerequisite for long-term acceptance of non-self genotypes within coral colonies.While some brooding corals have been shown to form genetic chimeras in their early life history stages under experimental conditions, this study provides the first genetic evidence of the occurrence of coral chimeras in the wild and of chimerism in a broadcast spawning species. We hypothesize that chimerism is more widespread in corals than previously thought, and suggest that this has important implications for their resilience, potentially enhancing their capacity to compete for space and respond to stressors such as pathogen infection

Directional dominance on stature and cognition in diverse human populations

Homozygosity has long been associated with rare, often devastating, Mendelian disorders(1), and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness(2). However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power(3,4). Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 x 10(-300), 2.1 x 10(-6), 2.5 x 10(-10) and 1.8 x 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples(5,6), no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection(7), this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been

Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity (vol 50, pg 26, 2017)

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity (vol 50, pg 26, 2018)

A.P.R. was supported by R01DK089256. A.W.H. is supported by an NHMRC Practitioner Fellowship (APP1103329). A.K.M. received funding from NIH/NIDDK K01DK107836. A.T.H. is a Wellcome Trust Senior Investigator (WT098395) and an NIH Research Senior Investigator. A.P.M. is a Wellcome Trust Senior Fellow in Basic Biomedical Science (WT098017). A.R.W. is supported by the European Research Council (SZ-245 50371-GLUCOSEGENES-FP7-IDEAS-ERC). A.U.J. is supported by the American Heart Association (13POST16500011) and the NIH (R01DK089256, R01DK101855, K99HL130580). B.K. and E.K.S. were supported by the Doris Duke Medical Foundation, the NIH (R01DK106621), the University of Michigan Internal Medicine Department, Division of Gastroenterology, the University of Michigan Biological Sciences Scholars Program and the Central Society for Clinical Research. C.J.W. is supported by the NIH (HL094535, HL109946). D.J.L. is supported by R01HG008983 and R21DA040177. D.R.W. is supported by the Danish Diabetes Academy, which is funded by the Novo Nordisk Foundation. V. Salomaa has been supported by the Finnish Foundation for Cardiovascular Research. F.W.A. is supported by Dekker scholarship–Junior Staff Member 2014T001 Netherlands Heart Foundation and the UCL Hospitals NIHR Biomedical Research Centre. F.D. is supported by the UK MRC (MC_UU_12013/1-9). G.C.-P. received scholarship support from the University of Queensland and QIMR Berghofer. G.L. is funded by the Montreal Heart Institute Foundation and the Canada Research Chair program. H.Y. and T.M.F. are supported by the European Research Council (323195; SZ-245 50371-GLUCOSEGENES-FP7-IDEAS-ERC). I.M.H. is supported by BMBF (01ER1206) and BMBF (01ER1507m), the NIH and the Max Planck Society. J. Haessler was supported by NHLBI R21HL121422. J.N.H. is supported by NIH R01DK075787. K.E.N. was supported by the NIH (R01DK089256, R01HD057194, U01HG007416, R01DK101855) and the American Heart Association (13GRNT16490017). M.A.R. is supported by the Nuffield Department of Clinical Medicine Award, Clarendon Scholarship. M.I.M. is a Wellcome Trust Senior Investigator (WT098381) and an NIH Research Senior Investigator. M.D. is supported by the NCI (R25CA94880, P30CA008748). P.R.N. is supported by the European Research Council (AdG; 293574), the Research Council of Norway, the University of Bergen, the KG Jebsen Foundation and the Helse Vest, Norwegian Diabetes Association. P.T.E. is supported by the NIH (1R01HL092577, R01HL128914, K24HL105780), by an Established Investigator Award from the American Heart Association (13EIA14220013) and by the Foundation Leducq (14CVD01). P.L.A. was supported by NHLBI R21HL121422 and R01DK089256. P.L.H. is supported by the NIH (NS33335, HL57818). R.S.F. is supported by the NIH (T32GM096911). R.J.F.L. is supported by the NIH (R01DK110113, U01HG007417, R01DK101855, R01DK107786). S.A.L. is supported by the NIH (K23HL114724) and a Doris Duke Charitable Foundation Clinical Scientist Development Award. T.D.S. holds an ERC Advanced Principal Investigator award. T.A.M. is supported by an NHMRC Fellowship (APP1042255). T.H.P. received Lundbeck Foundation and Benzon Foundation support. V.T. is supported by a postdoctoral fellowship from the Canadian Institutes of Health Research (CIHR). Z.K. is supported by the Leenaards Foundation, the Swiss National Science Foundation (31003A-143914) and SystemsX.ch (51RTP0_151019). Part of this work was conducted using the UK Biobank resource (project numbers 1251 and 9072)