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The circumpolar Arctic is currently facing multiple global changes that have the potential to alter the capacity of tundra soils to store carbon. Yet, predicting changes in soil carbon is hindered by the fact that multiple factors simultaneously control processes sustaining carbon storage and we do not understand how they act in concert. Here, we investigated the effects of warmer temperatures, enhanced soil nitrogen availability, and the combination of these on tundra carbon stocks at three different grazing regimes: on areas with over 50-yr history of either light or heavy reindeer grazing and in 5-yr-old exlosures in the heavily grazed area. In line with earlier reports, warming generally decreased soil carbon stocks. However, our results suggest that the mechanisms by which warming decreases carbon storage depend on grazing intensity: under long-term light grazing soil carbon losses were linked to higher shrub abundance and higher enzymatic activities, whereas under long-term heavy grazing, carbon losses were linked to drier soils and higher enzymatic activities. Importantly, under enhanced soil nitrogen availability, warming did not induce soil carbon losses under either of the long-term grazing regimes, whereas inside exclosures in the heavily grazed area, also the combination of warming and enhanced nutrient availability induced soil carbon loss. Grazing on its own did not influence the soil carbon stocks. These results reveal that accounting for the effect of warming or grazing alone is not sufficient to reliably predict future soil carbon storage in the tundra. Instead, the joint effects of multiple global changes need to be accounted for, with a special focus given to abrupt changes in grazing currently taking place in several parts of the Arctic.

The encroachment of shrubs into grasslands is common in terrestrial ecosystems dominated by grass. Land abandonment and favourable climatic trends in recent decades have favoured the expansion of shrubs into subalpine grasslands in many mountainous regions across Europe. The advance of the succession from grassland to shrubland is expected to have a major impact on ecosystem functioning. We used DNA metabarcoding to assess whether the structure of soil fungal communities varied along the succession from subalpine grassland to shrubland in the Pyrenees, and investigated whether shrub encroachment was associated with changes in soil properties. The expansion of shrubs increased the soil C:N ratio and/or reduced the N, P, or K contents. Plant-driven changes in soil properties were strongly associated with the compositional turnover of fungi, including arbuscular mycorrhizal, ectomycorrhizal, ericoid, root endophytic, saprotrophic, lichenised, and pathogenic fungi. Total richness and the richness of most functional groups were correlated with soil P, N, and the C:N or N:P ratios. We show that the interplay between abiotic factors (changes in soil properties) and biotic factors (occurrence and identity of shrubs) played a key role in the structure and uniqueness of soil fungal communities along the succession.

The encroachment of shrubs into grasslands is common in terrestrial ecosystems dominated by grass. Land abandonment and favourable climatic trends in recent decades have favoured the expansion of shrubs into subalpine grasslands in many mountainous regions across Europe. The advance of the succession from grassland to shrubland is expected to have a major impact on ecosystem functioning. We used DNA metabarcoding to assess whether the structure of soil fungal communities varied along the succession from subalpine grassland to shrubland in the Pyrenees, and investigated whether shrub encroachment was associated with changes in soil properties. The expansion of shrubs increased the soil C:N ratio and/or reduced the N, P or K contents. Plant-driven changes in soil properties were strongly associated with the compositional turnover of fungi, including arbuscular mycorrhizal, ectomycorrhizal, ericoid, root endophytic, saprotrophic, lichenised and pathogenic fungi. Total richness and the richness of most functional groups were correlated with soil P, N and the C:N or N:P ratios. We show that the interplay between abiotic factors (changes in soil properties) and biotic factors (occurrence and identity of shrubs) played a key role in the structure and uniqueness of soil fungal communities along the succession.

Maternally skewed transmission of traits has been associated with genomic imprinting and oocyte-derived mRNA. We report canine congenital eye malformations, caused by an amino acid deletion (K12del) near the N terminus of retinol-binding protein (RBP4). The disease is only expressed when both dam and offspring are deletion homozygotes. RBP carries vitamin A (retinol) from hepatic stores to peripheral tissues, including the placenta and developing eye, where it is required to synthesize retinoic acid. Gestational vitamin A deficiency is a known risk factor for ocular birth defects. The K12del mutation disrupts RBP folding in vivo, decreasing its secretion from hepatocytes to serum. The maternal penetrance effect arises from an impairment in the sequential transfer of retinol across the placenta, via RBP encoded by maternal and fetal genomes. Our results demonstrate a mode of recessive maternal inheritance, with a physiological basis, and they extend previous observations on dominant-negative RBP4 alleles in humans.

Maternally skewed transmission of traits has been associated with genomic imprinting and oocyte-derived mRNA. We report canine congenital eye malformations, caused by an amino acid deletion (K12del) near the N terminus of retinol-binding protein (RBP4). The disease is only expressed when both dam and offspring are deletion homozygotes. RBP carries vitamin A (retinol) from hepatic stores to peripheral tissues, including the placenta and developing eye, where it is required to synthesize retinoic acid. Gestational vitamin A deficiency is a known risk factor for ocular birth defects. The K12del mutation disrupts RBP folding in vivo, decreasing its secretion from hepatocytes to serum. The maternal penetrance effect arises from an impairment in the sequential transfer of retinol across the placenta, via RBP encoded by maternal and fetal genomes. Our results demonstrate a mode of recessive maternal inheritance, with a physiological basis, and they extend previous observations on dominant-negative RBP4 alleles in humans.

The availability of the genome sequence and genomic tools combined with the unique phenotypic diversity and breed structure has increased interest in dog as a large, physiologically relevant animal model for human genetic research. Dogs suffer from hundreds of hereditary conditions of which many resemble closely disorders in humans. Investigation of the genetic background of these conditions is important to understand the disease mechanisms and pathways for therapeutic options, to identify novel candidate genes for corresponding human conditions, and to inform the breeding programs. Remarkable resources have been established in the University of Helsinki for canine genetic research, including one of the largest canine DNA banks. This study has focused on degenerative eye diseases of unknown genetic cause. We combined efforts in basic and clinical veterinary research with a unique network of collaboration with dog breeders and owners to establish clinically relevant study cohorts for two types of retinal degeneration in Papillon and Phaléne, and in Swedish Vallhund, SV breeds and two different types of glaucoma in Dandie Dinmont Terriers, DDT and Norwegian Elkhounds, NE. Genome wide approaches with the latest genomic tools, including SNP arrays and exome sequencing were then utilized to identify causative loci and genes. We report breakthroughs in all projects and highlight shared molecular etiologies in canine and human vision disorders. The cause of the retinal degeneration in Papillons and Phalénes was found in the CNGB1 gene, which is important for the rod cell function and has been linked before to human retinal degenerations. A unique type of multifocal retinal degeneration was described in SV with association to the upregulation of the MERTK gene. MERTK mutations cause also retinal degeneration in humans. DDTs were found to present a primary closed angle glaucoma (PACG) with severe pectinate ligament dysplasia (PLD). The disease was mapped to a region on canin, Rotukoirien voimakas jalostus on tuottanut satoja perimältään uniikkeja rotuja ja rikastanut niihin satoja perinnöllisiä sairauksia, jotka muistuttavat läheisesti vastaavia sairauksia ihmisillä. Helsingin yliopistoon on rakennettu kansainvälisesti merkittävät tutkimusresurssit geenitutkimukseen, mukaan lukien yli 50 000 näytteen geenipankki, jota on hyödynnetty tässä tutkimuksessa. Tämä tutkimus keskittyi kahteen sokeuttavaan silmäsairauteen, verkkokalvonrappeumaan sekä glaukoomaan. Verkkokalvonrappeumassa silmän näköhavainnosta vastaavat solut vaurioituvat. Glaukoomassa puolestaan verkkokalvon sähköisestä viestinnästä vastaavat solut rappeutuvat ja näköhermo vaurioituu. Kohonnut silmänpaine liittyy usein sairauteen. Väitöskirjan osatyöt keskittyivät verkkokalvon rappeumaan papillon ja phaléneja sekä länsigöötanmaanpystykorva (LJP) roduissa, sekä glaukoomaan dandiedinmontinterriereissä (DDT) ja harmaa norjanhirvikoirissa (HNH). Tutkimuksessa yhdistyy kansainvälinen kliinisen ja perustutkimuksen yhteistyö sairauksien diagnosoinnissa ja näytteiden keräämisessä, jossa hyödynnetään tutkimusryhmän ainutlaatuista yhteistyöverkkoa koirien omistajien ja kasvattajien kanssa. Merkittävien tutkimusresurssien rakentamisen lisäksi tutkimuksessa saavutettiin läpimurtoja kaikissa osaprojekteissa. Papillon ja phaléne rotujen verkkokalvonrappeuma johtuu geenivirheestä CNGB1 geenissä, joka liittyy vastaavaan sairauteen myös ihmisillä. LJP rodussa kuvattiin uudentyyppinen verkkokalvonrappeuma, joka liittyy MERTK geenin toimintahäiriöön. DDT rodun glaukooma paikannettiin kromosomialueelle, jonka vastaavalla alueella on useita glaukoomaan liitettyjä geenialueita ihmisellä. HNH rodun glaukooma liittyy puolestaan virheeseen ADAMTS10 geenissä. Kyseinen geeni aiheuttaa Weill-Marchesani syndroomaan (WMS) ihmisillä, jossa potilailla diagnosoidaan poikkeavuuksia silmissä ja mm. nivelissä. Teoreettisen ymmärryksen lisäksi tutkimuksella on tärkeitä käytännön vaikutuksia. Geenilöydöt korostavat i