Browsing by Subject "Hybridization"

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  • Poczai, Peter; Matyas, Kinga Klara; Szabo, Istvan; Varga, Ildiko; Hyvönen, Jaakko; Cernak, Istvan; Gorji, Ahmad Mosapour; Decsi, Kincso; Taller, Janos (2011)
  • Kulmuni, Jonna; Nouhaud, Pierre; Pluckrose, Lucy; Satokangas, Ina; Dhaygude, Kishor; Butlin, Roger K. (2020)
    Speciation underlies the generation of novel biodiversity. Yet, there is much to learn about how natural selection shapes genomes during speciation. Selection is assumed to act against gene flow at barrier loci, promoting reproductive isolation. However, evidence for gene flow and selection is often indirect and we know very little about the temporal stability of barrier loci. Here we utilize haplodiploidy to identify candidate male barrier loci in hybrids between two wood ant species. As ant males are haploid, they are expected to reveal recessive barrier loci, which can be masked in diploid females if heterozygous. We then test for barrier stability in a sample collected 10 years later and use survival analysis to provide a direct measure of natural selection acting on candidate male barrier loci. We find multiple candidate male barrier loci scattered throughout the genome. Surprisingly, a proportion of them are not stable after 10 years, natural selection apparently switching from acting against to favouring introgression in the later sample. Instability of the barrier effect and natural selection for introgressed alleles could be due to environment-dependent selection, emphasizing the need to consider temporal variation in the strength of natural selection and the stability of the barrier effect at putative barrier loci in future speciation work.
  • Harmoinen, Jenni; von Thaden, Alina; Aspi, Jouni; Kvist, Laura; Cocchiararo, Berardino; Jarausch, Anne; Gazzola, Andrea; Sin, Teodora; Lohi, Hannes; Hytönen, Marjo K.; Kojola, Ilpo; Stronen, Astrid Vik; Caniglia, Romolo; Mattucci, Federica; Galaverni, Marco; Godinho, Raquel; Ruiz-Gonzalez, Aritz; Randi, Ettore; Munoz-Fuentes, Violeta; Nowak, Carsten (2021)
    Background Understanding the processes that lead to hybridization of wolves and dogs is of scientific and management importance, particularly over large geographical scales, as wolves can disperse great distances. However, a method to efficiently detect hybrids in routine wolf monitoring is lacking. Microsatellites offer only limited resolution due to the low number of markers showing distinctive allele frequencies between wolves and dogs. Moreover, calibration across laboratories is time-consuming and costly. In this study, we selected a panel of 96 ancestry informative markers for wolves and dogs, derived from the Illumina CanineHD Whole-Genome BeadChip (174 K). We designed very short amplicons for genotyping on a microfluidic array, thus making the method suitable also for non-invasively collected samples. Results Genotypes based on 93 SNPs from wolves sampled throughout Europe, purebred and non-pedigree dogs, and suspected hybrids showed that the new panel accurately identifies parental individuals, first-generation hybrids and first-generation backcrosses to wolves, while second- and third-generation backcrosses to wolves were identified as advanced hybrids in almost all cases. Our results support the hybrid identity of suspect individuals and the non-hybrid status of individuals regarded as wolves. We also show the adequacy of these markers to assess hybridization at a European-wide scale and the importance of including samples from reference populations. Conclusions We showed that the proposed SNP panel is an efficient tool for detecting hybrids up to the third-generation backcrosses to wolves across Europe. Notably, the proposed genotyping method is suitable for a variety of samples, including non-invasive and museum samples, making this panel useful for wolf-dog hybrid assessments and wolf monitoring at both continental and different temporal scales.
  • Cerqueira, Pablo Vieira; Gonçalves, Gabriela Ribeiro; Aleixo, Alexandre (2020)
    Hybridization is a relatively common phenomenon in birds, but it is probably underestimated due to our poor knowledge on the reproductive biology of several species. Here, we present the second case of intergeneric hybrid in the family Momotidae and the first case between Amazonian Motmot (Momotus momota) and Rufous Motmot (Baryphthengus martii). In addition to the field record documented herein, we searched for possible hybrids among 57 study skins and 175 photographs and videos publicly available in online databases. The overall plumage pattern of the hybrid individual recorded in the field was similar to that of the Rufous Motmot, except for the following features, which appear to have been inherited from the Amazonian Motmot: two narrow blue lines in the facial mask; distinct blue feathers on the pectoral spot; and central rectrices with terminal racquets. Among the database photos examined, we found a second possible hybrid, with the same diagnostic features present in the hybrid recorded in the field. Similarities in behavior and vocalizations, in addition to the scarcity of mates in the limits of the distributions of Amazonian and Rufous Motmots, may explain the occurrence of hybrids between them.
  • Rousi, Matti; Possen, Boy J. M. H.; Pulkkinen, Pertti; Mikola, Juha (2019)
    Silver (Betula pendula) and pubescent birch (B. pubescens) are the two main broad-leaved tree species in boreal forests and Subarctic areas, with great significance for both northern societies and ecosystems. Silver birch has more economical importance as it grows taller, but pubescent birch reaches much further North. The adaptability and genetic diversity of Subarctic birch populations are assumed to derive from inter- and intraspecific hybridization. Southern pollen clouds could in turn increase the adaptability of northern populations to warming climate. In the boreal forest zone of warmer climate, incompatibility reactions may prevent interspecific hybridization and much depends on the synchrony of flowering. Direct in situ observations are, however, mostly lacking and earlier results concerning the spatial and temporal match of flowering phenology between the species are contradictory. Conclusions based on pollen catches may also be biased as the pollen of silver and pubescent birch are notoriously difficult to sort out and the geographical origin of pollen is virtually impossible to determine. Here we employ direct flowering observations and reanalyze old pollen and seed production data, collected along a South-North gradient in Finland, to shed more light on these issues. Our results suggest that interspecific hybridization is an unlikely mechanism of adaptation in silver and pubescent birch as there is no significant overlap in flowering either near Subarctic or in more southern boreal areas (covering latitudes 60-68 degrees N). Long-distance southern gene flow also unlikely has importance in the adaptation of northern populations to a warming climate as heat sum requirements for flowering in northern and southern populations are equal and northern birches are therefore not receptive at the time of southern flowering. Long-term data of pollen and seed production in turn suggest that pubescent birch is more effective in seed production through the whole South North gradient, but increasingly so towards the North. However, it appears that this difference is not due to silver birch flowering and regeneration being more sensitive to interannual variation as earlier suggested. Although there are more factors than reproduction alone that can affect species distributions, these two findings indicate that climate warming may not significantly alter the relative abundances of silver and pubescent birch in Subarctic Fennoscandia.