cabells rossos ulls blaus

Un dels models de bellesa que possiblement tenim actualment són les persones amb cabells rossos i ulls blaus. No cal cercar gaire per trobar exemples de persones conegudes, models, actors, actrius amb aquest estàndard de bellesa. associació

Un estudi que s’acaba de publicar [1] demostra la funcionalitat d’una variant (SNP rs12821256 T/C) en una regió reguladora del gen KITLG (un lligand del Kit) amb la coloració del pèl i per tant dels cabells. De fet, la relació entre el color clar de cabells (rossos) amb aquesta variació ja fa temps que es coneix (Vegeu Figura). La novetat de l’estudi és la descripció detallada del mecanisme en el fol·licle pilós que porta a aquesta coloració del cabell. Utilitzant les eines bioinformàtiques d‘Ensembl veiem que aquest SNP està situat al cromosoma 12 a la cadena forward i que la variant ancestral és la T (cabells foscos). Com es pot veure al proporció de la variant C, que és la que està relacionada amb les cabells rossos és més freqüent (fins un 20%) en les poblacions d’anglesos-escocesos i fins un 19% en les poblacions de finlandesos (dates extretes d‘Ensembl i 1000 genomes).

populations

Allele freqeuncy of SNP rs12821256. AFR, All african indivuduals; AMR, all American individuals; EUR, all European Individuals. CEU, Northern Europeans from Utah; FIN, Finish; GBR, British in England and Scotland; IBS, Iberian; TSI, Toscani, Italy.

Tal i com deia abans, per ser “bonic” s’ha de tenir cabells rossos però també hi d’haver ulls blaus. Malgrat que els ulls blaus també sembla un caràcter poligènic, ja fa uns anys es va proposar que una sola variant d’un SNP (rs12913832 A/G) on la variant ancestral A comporta color fosc i la G el color clar d’ulls. Aquest SNP es troba en l’intró 86 del gen HERC2, un gen activador de la transcripció del gen OCA2 responsable, entre altres, de la coloració dels ulls. A l’any 2008, uns investigadors de la Universitat de Copenhagen [2] van demostrar que el canvi de la A per la G en el gen HERC2, i que en conseqüència desactiva el gen OCA 2 provocant el color d’ulls clars, podia haver aparegut fa uns 6000 -10000 anys en un únic individu de la durant la revolució neolítica.

 Bé, doncs ara si veieu un d’aquests models de bellesa de colors d’ulls blaus amb una melena rossa, és molt probable que sigui diferent d’un individu de colors d’ulls i cabells foscos en només dues variacions de les 3.5 x 109 posicions que té el nostre genoma.

  1. Guenther, C.A., et al., A molecular basis for classic blond hair color in Europeans. Nat Genet, 2014. 46(7): p. 748-752.
  2. Eiberg, H., et al., Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression. Human Genetics, 2008. 123(2): p. 177-187.
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Gene Flow and Maintenance of Genetic Diversity in Invasive Mosquitofish

journal.pone.0077028.g001

A new work from researches of the LIG and the IEA has been published in PLoS ONE. In this paper, the authors give insights in how gene flow between invasive populations shapes genetic diversity of Gambusia holbrooki in Mediterranean streams. Abstract:

Genetic analyses contribute to studies of biological invasions by mapping the origin and dispersal patterns of invasive species occupying new territories. Using microsatellite loci, we assessed the genetic diversity and spatial population structure of mosquitofish (Gambusia holbrooki) that had invaded Spanish watersheds, along with the American locations close to the suspected potential source populations. Mosquitofish populations from the Spanish streams that were studied had similar levels of genetic diversity to the American samples; therefore, these populations did not appear to have undergone substantial losses of genetic diversity during the invasion process. Population structure analyses indicated that the Spanish populations fell into four main clusters, which were primarily associated with hydrography. Dispersal patterns indicated that local populations were highly connected upstream and downstream through active dispersal, with an average of 21.5% fish from other locations in each population. After initially introducing fish to one location in a given basin, such dispersal potential might contribute to the spread and colonization of suitable habitats throughout the entire river basin. The two-dimension isolation-by-distance pattern here obtained, indicated that the human-mediated translocation of mosquitofish among the three study basins is a regular occurrence. Overall, both phenomena, high natural dispersal and human translocation, favor gene flow among river basins and the retention of high genetic diversity, which might help retain the invasive potential of mosquitofish populations.

More information can be found here.

Adult female of G. holbrooki

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Díez-del-Molino D, Carmona-Catot G, Araguas R-M, Vidal O, Sanz N, et al. (2013) Gene Flow and Maintenance of Genetic Diversity in Invasive Mosquitofish (Gambusia holbrooki). PLoS ONE 8(12): e82501. doi:10.1371/journal.pone.0082501

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[Conferencia] The Phylogeny of Little Red Riding Hood

Nos complace invitaros a la charla que impartirá el Dr. Oriol Vidal (colaborador en COOL GENES y Profesor Titular en el Área Genètica de la Universitat de Girona) el próximo Miércoles 18 de Diciembre a las 12:00 en la Sala de Graus de la Facultat de Ciències.

The Phylogeny of Little Red Riding Hood o un exemple de ‘phylomemetics’: l’anàlisi filogenètico dels fenòmens culturals

¡Os esperamos!

Eleccions a RECTOR/A a la UdG

baner eleccions

Avui comença la campanya electoral de les eleccions al Rectorat de la UdG que es celebraran el proper 19 de Novembre. Trobareu tota la informació sobre el procés electoral a la Seu Electrònica de la UdG. També podreu consultar els programes dels dos candidats a les seves pàgines web (Quim Ciurana y Sergi Bonet). 

PARTICIPA!

Colonization routes of the invasive mosquitofish introduced to Europe

paper_gambusia__nuri

A new work from researches of the LIG has been released today in the Biological Invasions journal. In this paper, the authors try to clarify the main routes of colonization of the European continent by the highly invasive species of freshwater fish Gambusia holbrooki. Abstract:

Biological invasions are considered one of the main anthropogenic factors that reduce the abundance of native species. Understanding the patterns of population structure and behavior of introduced species is important to determine invasion sources and pathways. We set out to advance our knowledge about the invasive mosquitofish Gambusia spp. by screening variation at six microsatellite loci. We also evaluated six American samples (four of G. holbrooki and two of G. affinis) to identify the most likely source of the populations that established in Europe. The results showed that most introduced populations harbored a considerable amount of gene diversity, probably because of multiple introductions and secondary contacts. Populations displayed strong genetic differentiation that was mainly associated with geographical distance. At least two main routes of colonization of G. holbrooki seem to have occurred in Europe. The first, was consistent with the historical records of the species invading the Iberian Peninsula. A second, and more recent colonization, probably occurred in Greece and, from there, France.

Further information about the paper can be accessed here.

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Sanz, N.Araguas, R.M. Vidal, O.Diez-del-Molino, D.Fernández-Cebrián, R.García-Marín, J.L. (2013) Genetic characterization of the invasive mosquitofish (Gambusia spp.) introduced to Europe: population structure and colonization routes. Biological Invasions. October 2013, Volume 15, Issue 10, pp 2333-2346

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