Genetics and Breeding

Genetic parameters (heritability, phenotypic and genetic correlations) were estimated for a range of visual and measured wool traits recorded from the 2008 shearing of the initial cohort of Merino progeny born into the Sheep CRC’s Information Nucleus Flock. The aim of this initial analysis was to determine the feasibility of selectively breeding Merino sheep for softer, whiter, more photostable wool and to quantify the likely impact on other wool production and quality traits. The estimates of heritability were high for handle and clean colour (0.86 and 0.70, respectively) and moderate for photostability (0.18), with some evidence of maternal effects for both handle and photostability. The phenotypic correlations between handle and clean colour and between handle and photostability were close to zero, indicating that achieving the ‘triple’ objective of softer, whiter, more photostable wool in the current generation through phenotypic selection alone would be difficult. There was evidence of an antagonistic relationship between handle and photostability (–0.36), such that genetic selection for softer wool will produce less photostable wool that will yellow on exposure to UV irradiation. However genetic selection for whiter wool is complementary to photostability and will result in whiter wool that is less likely to yellow. Genetic selection to improve handle, colour and photostability can be achieved with few detrimental effects on other visual and measured wool traits, particularly if they are included in an appropriate selection index. more »

MicroRNAs (miRNAs) are small, non-coding 21–25 nt RNA molecules that play an important role in regulating gene expression. Little is known about the expression profiles and functions of miRNAs in skin and their role in pigmentation. Alpacas have more than 22 natural coat colors, more than any other fiber producing species. To better understand the role of miRNAs in control of coat color we performed a comprehensive analysis of miRNA expression profiles in skin of white versus brown alpacas. more »

A cDNA library from white alpaca (Vicugna pacos) skin was constructed using SMART technology to investigate the global gene expression profile in alpaca skin and identify genes associated with physiology of alpaca skin and pigmentation. A total of 5359 high-quality EST (expressed sequence tag) sequences were generated by sequencing random cDNA clones from the library. Clustering analysis of sequences revealed a total of 3504 unique sequences including 739 contigs (assembled from 2594 ESTs) and 2765 singletons. BLAST analysis against GenBank nr database resulted in 1287 significant hits (E-value < 10−10), of which 863 were annotated through gene ontology analysis. Transcripts for genes related to fleece quality, growth and coat color (e.g. collagen types I and III, troponin C2 and secreted protein acidic and rich in cysteine) were abundantly present in the library. Other genes, such as keratin family genes known to be involved in melanosome protein production, were also identified in the library. Members (KRT10, 14 and 15) of this gene family are evolutionarily conserved as revealed by a cross-species comparative analysis. This collection of ESTs provides a valuable resource for future research to understand the network of gene expression linked to physiology of alpaca skin and development of pigmentation. more »

If any of the assertions below contradict what you believe about alpaca base coat color genetics, it’s definitely worth reading this blog post and continuing on to a very friendly, fun-loving statistical analysis that is available in our website’s library! 1. First, all white alpacas can produce color when they are bred to it. There is no such thing as a homozygous dominant white animal. In fact, a pink-skinned white is in some ways as recessive a creature as a true black. 2. What’s more, many fawns are not just “dilute” but carry a white base coat color allele, which acts to dilute a brown allele in the production of the phenotypic coat color. You can actually breed two fawns together and get a homozygous white. 3. White breeders, no need to rely on those pure-white pedigrees to make sure you don’t produce fawns and browns. Turns out a brown allele can’t really hide itself well phenotypically. 4. Color breeders, to introduce white genetics into a color breeding program with lower odds of producing white offspring, breed that white animal to brown. The darker, the better. more »

To make predictions about coat color, or almost any other trait, in cria from specific breedings you need to understand some basic rules of genetics. Coat color is determined by genetics. When people say something is genetically determined, what they are really talking about is DNA. DNA is what codes for all of the proteins (things like hemoglobin, albumin, melanin, insulin, keratin tissues, hormones all the stuff that make up an alpaca), and for the instructions on how, when and where to make these proteins within the alpaca. Segments of DNA that code for proteins are called genes. more »