Tag: "fleece"

  • Fleece Variation in Alpaca (Vicugna pacos): A Two-Locus Model for the Suri/Huacaya Phenotype

    Genetic improvement of fibre-producing animal species has often induced transition from double coated to single coated fleece, accompanied by dramatic changes in skin follicles and hair composition, likely implying variation at multiple loci. Huacaya, the more common fleece phenotype in alpaca (Vicugna pacos), is characterized by a thick dense coat growing perpendicularly from the body, whereas the alternative rare and more prized single-coated Suri phenotype is distinguished by long silky fibre that grows parallel to the body and hangs in separate, distinctive pencil locks. A single-locus genetic model has been proposed for the Suri-Huacaya phenotype, where Huacaya is recessive. more »
  • Characterization of the Effect of Melanocortin 1 Receptor, a Member of the Hair Color Genetic Locus, in Alpaca (Lama pacos) Fleece Color Differentiation

    Little is known about the inheritance and influence of the fleece color gene Melanocortin 1 Receptor (MC1R). Melanocortin 1 Receptor (MC1R) is a well-known gene responsible for red versus black fleece pigmentation and is hypothesized to be a candidate gene for variation in alpaca coloration patterns. Inheritance of red versus black pigmentation in the context of genetic mutation is well understood in many domesticated mammals. We characterized the MC1R gene in a population of multi-colored alpacas in order to better understand its effect on coat color in the alpaca. Our characterization of the alpaca MC1R gene revealed 11 mutations. Of these one is a 4 bp deletion, four are silent mutations and six are single nucleotide polymorphisms (SNPs) that alter the amino acid sequence (T28V, M87V, S126G, T128I, S196F, R301C). No mutation correlated completely with fleece color in alpacas at the MC1R locus. This may be due to the epistatic relationship of MC1R with other coat color genes especially agouti signaling protein (ASIP). more »
  • Sources of Variation in Fibre Diameter Attributes of Australian Alpacas and Implications for Fleece Evaluation and Animal Selection

    Sources of variation in fibre diameter attributes of Australian alpacas and implications for fleece evaluation and animal selection were investigated using data collected in the years 1994–97, from 6 properties in southern Australia. Data were analysed using REML (multiple regression analysis) to determine the effect on mean fibre diameter (MFD) and coefficient of variation of MFD (CV(FD)) of age, origin (property), sex (entire male, female), breed (Huacaya, Suri), liveweight, fibre colour, individual, and interactions of these effects. The mean (n = 100) age (range) was 4.2 years (0.1–11.9), liveweight 72.0 kg (12.0–134 kg), MFD 29.1 μm (17.7–46.6 μm), CV(FD) 24.33% (15.0–36.7%). A number of variables affected MFD and CV(FD). MFD increased to 7.5 years of age, and correlations between MFD at 1.5 and 2 years of age with the MFD at older ages were much higher than correlations at younger ages. Fibre diameter 'blowout' (increase with age) was positively correlated with the actual MFD at ages 2 years and older. There were important effects of farm, and these effects differed with year and shearing age. Suris were coarser than Huacayas with the effect reducing with increased liveweight; there was no effect of sex. Fleeces of light shade were 1 μm finer than dark fleeces. CV(FD) declined rapidly between birth and 2 years of age, reaching a minimum at about 4 years of age and then increasing; however, CV(FD) measurements on young animals were very poor predictors of CV(FD) at older ages, and the response of CV(FD) to age differed with farm and year. Suris had a higher CV(FD) than Huacayas on most properties, and MFD, liveweight, and sex did not affect CV(FD). Fleeces of dark shade had higher CV(FD) than fleeces of light shade in 2 of the years. It is concluded that there are large opportunities to improve the MFD and CV(FD) of alpaca fibre through selection and breeding. The potential benefit is greatest from reducing the MFD and CV(FD) of fibre from older alpacas, through reducing the between-animal variation in MFD and CV(FD). Sampling alpacas at ages more »
  • Pigment, Curvature, and a Caution About the Assumed Heritability of Phenotypic Fleece Character

    People who process alpaca fiber into products are well aware that dark fleece behaves differently than lighter fleece in processing as well as in many final products. Even if the fineness and uniformity of a batch of dark fleeces is identical to that of a batch of white, for instance, the yarns made from those fleeces will be denser (and heavier) at the same gauge and exhibit less memory, making its performance in end products different than yarns made from light fiber. The reason for the difference is that the fibers making up the fleeces at the darker end of the spectrum of alpaca colors have less curvature than those from lighter-colored fleeces of similar fineness and length. The question is, why? The analysis below hints at a possible answer. more »
  • Inheritance of Suri and Huacaya Type of Fleece in Alpaca

    The inheritance of the two types of fleece, Suri and Huacaya, observed in Alpaca (Lama pacos L.) is still not clearly defined. The objective of this work is to investigate the patter of inheritance of these two phenotypes, throughout 588 Suri x Suri and 2126 Huacaya x Huacaya offspring. The single gene and the three two-phenotype epistatic models were tested in the 19 Suri x Suri segregating families. The single dominant gene hypothesis best fitted our segregation data and could be, therefore, accepted (Gt=20.276, P=0.378). The gene frequency of the recessive Huacaya allele was 0.295, being the frequency of the dominant Suri allele 0.705. The frequency of heterozygotes, estimated in the whole population and among dominant individuals, was 0.416 and 0.455, respectively, with a “carrier” Suri to Huacaya ratio of 4.780. In three Huacaya families, 3 Suri were born, as a result of a new dominant mutation on some germinal lines of Huacaya animals. The direct mutation rate can be estimated at 0.0014. more »

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