Phenotypes resulting from Huacaya by Huacaya, Suri by Huacaya and Suri by Suri alpaca crossings.

Abstract

Proc . Assoc . Advmt .Anim . Breed. Genet . Vol12 PHENOTYPES RESULTING FROM HUACAYA BY HUACAYA, SURI BY HUACAYA AND SURI BY SURI ALPACA CROSSINGS R.W Ponzoni', D.J. Hubbard*, RV. Kenyon', C.D. Tuckwell*, B.A. McGregor3, A. Howse', I. Carmichael4 and G.J. Judson4 `Sout h Australia nResearc h an d Developmen tInstitute , O bo x 397, Adelaide ,S A 5001 GP *Primar yIndustrie sSout h Australia ,c/o Th e Universit yof Adelaide , Roseworthy ,S A 537 1 `Victoria n Institut eof Anima l Science , Attwood ,VI C 3049 4Centra lVeterinar yLaboratories ,Primar y Industrie s Sout h Australia ,Glenside ,S A 5065 SUMMARY Dat a o n 145 Huacay a sir e b y Huacay a dam , 24 Sur i sir e b y Huacay a da m an d 35 Sur i sir e b y Suri da m matin g record s (an d thei r correspondin gprogeny) wer e used t o determin e th e mod e of inheritanc eof th e Huacay a an d Sur i featur e i n Alpacas . Th e result s indicate dcontro l by a single gen e (o r b y a n haplotype) ,an d dominanc eof th e allel e responsibl efor th e Sur i type (AIFS ) over tha t responsibl efo r th e Huacay a typ e (A@). Keywords: Alpaca , Huacaya , Suri , crosses , inheritance. INTRODUCTION Tw o distinc tphenotype sca n b e identifie damon g Alpaca s (Lam apaces) , th e Huacay a an d th e Suri (Call e Escoba r 1984, Bustinz aChoqu e 1985, Wheele r 1991, Novo a an d Wilso n 1992). Mos t (-90 pe r cent ) Alpaca s belon gt o th e Huacay a type . Huacaya sca n b e distinguishe d m Suri s b y their fro fleec e characteristics . Th e Huacaya' s fibr e i s sometime scrimped ,an d ma y b e describe da s similar t o tha t of Corriedal eo r of stron g woo l Merin o sheep . Th e staple sgro w perpendicula r o th e skin t surface . By contrast ,th e Sur i fleece ha s a longe r an d lustrou sfibre , whic h `hangs ' fro m th e skin surfac e a s i n Lincol n shee p o r Angor a goats . Th e Sur i staple s sho w ringle t formations characteristi cof Angor a goats , an d thes e par t alon g th e bac k of th e anima lexposin gth e skin. Whe n crosse s ar e mad e betwee nHuacay a an d Sur i Alpaca s th e progen y distinctl yfal l int o on e or th e othe r type (Call e Escoba r 1984). Thi s suggest sth e presenc e of a majo r gen e influencin gthe trait . Novo a an d Wilso n (1992) indicat etha t Sur i coul d b e dominan tove r Huacaya , wherea sCalle Escoba r (1984) suggest s tha t th e opposit e coul d b e true . Bot h reference s stres s tha t further mating s shoul d b e rigorousl y studied . Not e tha t ther e i s anecdota l informatio n(e.g . Anonymous 1994, C . Tuckwel l - persona l communication )abou t a thir d typ e (Chili) , whic h i s no t well documente dan d i s no t deal t wit h here. I n this pape r w e repor t result s fro m a n Alpaca researc h projec t describe d b y Tuckwel l et al. (1996). I t i s suggeste dtha t th e trai t i s controlle db y a singl egen e (o r b y a n haplotype )an d tha t the Sur i allel e i s dominan tove r th e Huacay a allele. 136 Proc. Assoc. Advmt. Anim. Breed Genet. Vol12 MATERIALS AND METHODS The data analysed here are part of a broader Alpaca study involving five cooperating producers (Tuckwell et al. 1996). Full pedigrees were kept on the animals involved in the project, and the phenotype (Huacaya or Suri) of progeny and of both parents was recorded. A total of 204 mating records (and their corresponding progeny) were available for analysis. The mating combinations were: 145 Huacaya sire by Huacaya dam, 24 Suri sire by Huacaya dam, and 35 Suri sire by Suri dam. There were no Huacaya sire by Suri dam matings. Initially, sex of the progeny and the interaction of sex with mating combination were included in a linear model to ascertain whether there was significant sex effect, and (or) a significant sex by mating combination interaction on progeny phenotype. Both effects were non significant pO.6) and were ignored in all later analyses. A single gene (AIF, for Alpaca fleece) mode of inheritance was postulated, with two alleles: AZ@ and AZ@, the latter being dominant over the former. Deviations from the expected phenotypic ratios among the progeny resulting from the different mating combinations were tested by chisquare (corrected for continuity). RESULTS Huacaya sire by Huacaya dam matings resulted in 145 Huacaya and no Suri progeny. A single phenotype among the progeny suggests that the parents are homozygous. Also, because no Suri phenotypes were produced from Huacaya sire by Huacaya dam matings one may assume that the A@ allele is recessive. The results fit with the hypothesis of a single gene and dominance of the AIN allele over the AfFh allele. Suri sire by Huacaya dam matings resulted in 13 Huacaya and 11 Suri progeny. These numbers do not deviate significantly (x2 , df = 0.21, P=O.65) Erom a I:1 ratio. A 1:l ratio suggests control by a single gene and that one of the parents (the Suri sires in this case) is heterozygous. Suri sire by Suri dam matings resulted in 6 Huacaya and 29 Suri progeny. These numbers do not deviate significantly (x2, df= 1.4, P-0.24) from a 1:3 ratio. A I:3 ratio suggests control by a single gene and that both parents (Suri sires and dams) are heterozygous. We examined the progeny of each Suri sire in our data base. Under the postulated mode of inheritance, a single Huacaya pro eny from a Suri sire would be proof that the sire is heterozygous (i.e. carrier of the AIF a gene). Out of a total of 11 Suri sires in our data base, 9 could be deemed heterozygous using this criterion. The other 2 sires had too few (1 and 3) progeny to be classified as homozygous or heterozygous. Suri dams had insufficient number of progeny to ascertain their genotype, but one may assume that among them the gene frequency is similar to that among sires (i.e. most, if not all, dams are heterozygous). Heterozygosity among Suris could be due to frequent crossing with Huacaya or to heterozygous advantage. We know that crosses between the two phenotypes are frequent, but we are not aware of evidence regarding the possibility of heterozygous advantage. 137 Proc. Assoc. Advmt, Anim. Breed. Genet. Vol12 DISCUSSION Results from Huacaya by Suri matings have been reported by Novoa and Wilson (1992) and by Flint (1996). Although we lack depth of knowledge about the data sets involved, some comparisons may be made with our fmdings. Huacaya by Huacaya matings only produced Huacaya offspring in Novoa and Wilson's study, which is in agreement with our fmdings. However, out of 8446 such matings Flint (1996) reports that 0.45 per cent produce Suri progeny. This is not consistent with our hypothesis that Huacayas are homozygous recessive, but such a small percentage of Suri progeny could be accounted for by errors in recording parental and progeny phenotypes, or when entering the data for analysis. Suri by Huacaya matings result in a 1: 1 ratio in Flint's data (x2i df = 0.06, P=O.S), but the deviation from the expected values borders significance (x2 1df = 3.08, P=O.OS)in Novoa and Wilson's report. Note, however, that in the latter case there are only 12 progeny resulting from this mating combination. In both, Flint's and Novoa and Wilson's reports there is a significant (PcO.01) departure from a 1:3 ratio among progeny from Suri by Suri matings, due to an excess of Suri phenotypes. Unfortunately, neither study attempts to ascertain the genotypes of the parents, and the results could be simply due to the presence of a fraction of homozygous Suri parents. In summary, the results presented by Novoa and Wilson (1992) and by Flint (1996) are not in complete agreement with ours, but the discrepancies have possible explanations and the evidence is not sufficient disprove our hypothesis. We conclude that our results are consistent with the postulated mode of inheritance (a single gene and two alleles, A@ dominant over AI@). The model was chosen because it is the simplest possible one. Note, however, that the same results could be obtained if the trait were not controlled by a single gene, but by a group of very closely linked genes (haplotype) that were inherited together. Further analyses of data should contribute to a greater understanding of the genetic mechanisms involved in the expression of the Huacaya and Suri phenotypes. In the meantime, rules and regulations drawn up by the Australian Alpaca Association regarding the registration and status of Huacaya and Suri animals resulting from different mating combinations should take into account current knowledge about the inheritance of this Alpaca feature. ACKNOWLEDGMENTS The Rural Industries Research and Development Corporation provides fmancial support for this project. We are very grateful for the cooperation of the Alpaca owners, the property managers and the Australian Alpaca Association. Mr C.H.S. Dolling assisted with the interpretation of COGNOSAC guidelines for gene nomenclature. 138 I Proc. Assoc. Advmt. Anim. Breed. Genet. Vol12 REFERENCES Anonymous ( 1994) Alpacas Australia, Issue Number 1, p.47. Bustinza Choque, V. (1985) 'Razz de Alpacas de1 Altiplano: Suri y Wacaya', Universidad National de1 Altiplano, Instituto de Investigaciones para el Desarrollo Social de1 Altiplano, Puno, Peru. Calle Escobar, R. (1984) 'Animal Breeding and Production of American Camelids', Talleres Graficos de ABRIL, Lima, Peru. Flint, J.R. (1996) In 'Notes of Registration Sub-Committee, Australian Alpaca Association', 4 pp. Novoa, C. and Wilson, T. (1992) In 'The management of global animal genetic resources', FA0 Animal Production and Health Paper 104, pp. 189-203, Rome, Italy. Tuckwell, C.D., Ponzoni, R.W., McGregor, B.A., Carmichael, I., Judson, G.J. and Kenyon, R. (1996) An Australian Alpaca Research Project - Some preliminary data. Proceedings of the Australian Alpaca Association Conference, Brisbane, Queensland, pp. 153- 162. Wheeler, Jane C. (1991) In 'Avarices y Perspectivas de1 Conocimiento de 10s Camelidos Sud Americanos', Ch. 1, pp. 1l-48, Oticina Regional de la FAO, Santiago, Chile. 139