Genetic variation of ASIP and MC1R in past and present sheep of Gotland
Ovine black coat colour is determined by the MC1R (Melanocortin 1 receptor) and ASIP (Agouti signalling peptide) genes at the Agouti and Extension loci. The black phenotype is caused by production of eumelanin by melanocytes, whereas yellow-tan or light phenotype is the result of phaeomelanin synthe...
| Autor principal: | |
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2015
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| Acceso en línea: | https://stud.epsilon.slu.se/7613/ |
| _version_ | 1855571213866237952 |
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| author | Westberg Sunesson, Kristina |
| author_browse | Westberg Sunesson, Kristina |
| author_facet | Westberg Sunesson, Kristina |
| author_sort | Westberg Sunesson, Kristina |
| collection | Epsilon Archive for Student Projects |
| description | Ovine black coat colour is determined by the MC1R (Melanocortin 1 receptor) and ASIP (Agouti signalling peptide) genes at the Agouti and Extension loci. The black phenotype is caused by production of eumelanin by melanocytes, whereas yellow-tan or light phenotype is the result of phaeomelanin synthesis. The ovine MC1R gene has two known alleles: the wildtype (E+) and the dominant black (ED) alleles. Two missense mutations (c.218T>A and c.361G>A) constitute ED. The presence of a third allele, the e allele, is proposed and believed to give rise to phaeomelanic phenotype. There are many alleles in the ASIP gene, the two most important are the dominant white (Awt) and the most recessive black (Aa). Two mutations are alleged to cause recessive black phenotype: a missense mutation g.5172T>A and a nonsense mutation, a five base pairs (bp) deletion (D5). However, not all black sheep, lacking the dominant black allele, are homozygous for at least one of the above mentioned ASIP mutations. A third mutation, a nine bp deletion (D9), is identified but its complete phenotypic influence is unknown.
The aim of this study was to compare the presence of ED and the ASIP mutations in past and present sheep native to the Swedish island of Gotland in the Baltic Sea, to gain knowledge regarding the coat colour phenotype in these sheep. Fragments of the genes mentioned above concerning parts of interest were sequenced from present Gute Sheep and Gotland Pelt Sheep (breeds native to Gotland) using Sanger sequencing and from ovine remains contextually dated to the Medieval Times and the Iron Age found on Stora Karlsö, Gotland, (as well as some sheep remains from the Swedish mainland) using pyrosequencing. All present sheep possessed the E+E+ genotype. The three black sheep included in this study were homozygous for at least one of g.5172T>A or D5. Eighty-two grey present sheep possessed several diplotypes, but none was homozygous for g.5172T>A or D5. The ancient individuals possessed TT of c.218 and GG of c.361G>A. Two ancient individuals possessed the A of c.361G>A of ED, indicating that this mutation was indeed present in medieval sheep of Gotland and in mainland sheep of the 7th century. While some of the ancient sheep possessed the wildtype genotype of D5, no genotype could be determined for g.5172T>A. The full genetic background for recessive black coat colour could not be elucidated since some black sheep, that lack ED, are not always homozygous for D5 and/or g.5172TT>A. |
| format | Second cycle, A2E |
| id | RepoSLU7613 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2015 |
| publishDateSort | 2015 |
| record_format | eprints |
| spelling | RepoSLU76132016-04-09T23:15:08Z https://stud.epsilon.slu.se/7613/ Genetic variation of ASIP and MC1R in past and present sheep of Gotland Westberg Sunesson, Kristina Animal genetics and breeding Ovine black coat colour is determined by the MC1R (Melanocortin 1 receptor) and ASIP (Agouti signalling peptide) genes at the Agouti and Extension loci. The black phenotype is caused by production of eumelanin by melanocytes, whereas yellow-tan or light phenotype is the result of phaeomelanin synthesis. The ovine MC1R gene has two known alleles: the wildtype (E+) and the dominant black (ED) alleles. Two missense mutations (c.218T>A and c.361G>A) constitute ED. The presence of a third allele, the e allele, is proposed and believed to give rise to phaeomelanic phenotype. There are many alleles in the ASIP gene, the two most important are the dominant white (Awt) and the most recessive black (Aa). Two mutations are alleged to cause recessive black phenotype: a missense mutation g.5172T>A and a nonsense mutation, a five base pairs (bp) deletion (D5). However, not all black sheep, lacking the dominant black allele, are homozygous for at least one of the above mentioned ASIP mutations. A third mutation, a nine bp deletion (D9), is identified but its complete phenotypic influence is unknown. The aim of this study was to compare the presence of ED and the ASIP mutations in past and present sheep native to the Swedish island of Gotland in the Baltic Sea, to gain knowledge regarding the coat colour phenotype in these sheep. Fragments of the genes mentioned above concerning parts of interest were sequenced from present Gute Sheep and Gotland Pelt Sheep (breeds native to Gotland) using Sanger sequencing and from ovine remains contextually dated to the Medieval Times and the Iron Age found on Stora Karlsö, Gotland, (as well as some sheep remains from the Swedish mainland) using pyrosequencing. All present sheep possessed the E+E+ genotype. The three black sheep included in this study were homozygous for at least one of g.5172T>A or D5. Eighty-two grey present sheep possessed several diplotypes, but none was homozygous for g.5172T>A or D5. The ancient individuals possessed TT of c.218 and GG of c.361G>A. Two ancient individuals possessed the A of c.361G>A of ED, indicating that this mutation was indeed present in medieval sheep of Gotland and in mainland sheep of the 7th century. While some of the ancient sheep possessed the wildtype genotype of D5, no genotype could be determined for g.5172T>A. The full genetic background for recessive black coat colour could not be elucidated since some black sheep, that lack ED, are not always homozygous for D5 and/or g.5172TT>A. Svart ullfärg hos får bestäms av två gener: MC1R (melanocortin 1 receptor) och ASIP (Agouti signaling peptide) på Extension och Agouti loci. Den svarta fenotypen orsakas av melaninproduktion från melanocyter, medan ljus fenotyp sker när melanocyterna syntetiserar faeomelanin. Det finns två känna alleler i fårens MC1R: vildtypen (E+) och den dominant svarta (ED). ED består av två punktmutationer: c.218T>A och c.361G>A. Det föreslås förekomma ytterligare en allel, allel e, som tros ge upphov till faeomelanin-produktion. Det finns flera alleler i ASIP. De två viktigaste är den mest dominanta vita (Awt) och den mest recessiva svarta (Aa). Två mutationer i ASIP genen orsakar recessiv svart ullfärg: g.5172T>A och en 5 baspars deletion (D5). Alla svarta får (som saknar ED) är ändå inte homozygota för en av ASIP mutationerna. En tredje mutation, en 9 baspars deletion (D9) är identifierad, men dess fulla påverkan på nedärvning av svart ullfärg är inte känd. Målet med denna studie var att jämföra förekomsten av ED och ASIP mutationerna hos nutida och forntida gotländska får för att kunna avgöra ullfärgen hos dessa får. Intressanta delar av DNA hos de ovannämnda generna sekvenserades från blodprover från nutida gutefår och gotlandsfår (gotländska raser) och från kvarlevor från får som kontextuellt hade daterats till tidig medeltid och järnåldern som hittats på Stora Karlsö utanför Gotland. Även några kvarlevor från fastlandet sekvenserades. Sanger sekvensering användes för de nutida fåren och pyrosekvensering för de gamla fåren. Alla nutida får hade genotypen E+E+. De tre svarta nutida fåren som ingick i studien var homozygota för en av g.5172T>A och D5. De grå fåren hade olika diplotyper. Några av de gamla fåren var homozygota för TT (c.218T>A) och GG (c.361G>A) Två individer hade genotypen AG på position c.361. Detta resultat antyder att denna mutation, som utgör en del av ED, fanns hos svenska får på Gotland under tidig medeltid och på fastlandet redan på 600-talet. Några av de gamla fåren hade den normala vildtypen av D5 (de saknade deletionen). Inga genotyper för g.5172T>A kunde bestämmas. Den fulla genetiska bakgrunden för recessiv svart ullfärg kunde inte klargöras då svarta får, som saknar den dominanta svarta allelen, inte behöver vara homozygota för någon av ASIP mutationerna. 2015-02-16 Second cycle, A2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/7613/11/westberg_sunesson_k_150309.pdf Westberg Sunesson, Kristina, 2015. Genetic variation of ASIP and MC1R in past and present sheep of Gotland. Second cycle, A2E. Uppsala: (VH) > Dept. of Animal Breeding and Genetics (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-670.html> urn:nbn:se:slu:epsilon-s-4172 eng |
| spellingShingle | Animal genetics and breeding Westberg Sunesson, Kristina Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title | Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title_full | Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title_fullStr | Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title_full_unstemmed | Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title_short | Genetic variation of ASIP and MC1R in past and present sheep of Gotland |
| title_sort | genetic variation of asip and mc1r in past and present sheep of gotland |
| topic | Animal genetics and breeding |
| url | https://stud.epsilon.slu.se/7613/ https://stud.epsilon.slu.se/7613/ |