Major Genes in Wool

1. Major Genes in Wool • Ian Purvis and Ian Franklin • CSIRO Livestock Industries • Armidale

2. Orientation • A bit Merino-centric • A bit Australian-ocentric • Unashamedly industrially focussed • But There is some biology for those whose upbringing was other than quantitative!

3. Structure • Highlight industrial issues • The biology of wool growth • Known genes of major effect - • Knowledge (or lack of it) from linkage studies • Opportunities and needs

4. Global Wool Statistics

5. Characteristics that Determine the Value of Merino Wool (19.5 to 25.0 Microns) Fibre Diameter 70% 2002/03 Additional Measurements 2% Staple Strength 11% Point of Break 2% Marketing Factors 6% Style MV <1% 2% Length 5% Color <1% Source: The Woolmark Company

6. A New Zealand Perspective MerinoCrossbred Fibre diameter ***** Staple length **** VM **** Colour **** Staple length *** Staple strength *** Staple strength *** Bulk *** Colour ** VM ** Bulk * Fibre diameter ** Medullation Medullation *

7. Luxury Fibre Market 2001/02 ASW = Australian Superfine Wool Cashmere (12.5-21um) Mohair (24-46um) ASW (15.6-16.5um) ASW (17.6-18.5um) ASW (16.6-17.5um) Alpaca (20-34um) Production Source: The Woolmark Company, Seal International, AWEX

8. Message • A textile fibre under pressure • Good economic information • Must be vitally aware of end use

9. What is wrong with Wool?

10. What’s Wrong with Wool • For Apparel Wool: • Mean Fibre Diameter – in relation to competitors for apparel wear fabrics

11. Fineness of fibre competitors Australian wool clip average 22.1 µm polyester yarn & staple fibre 10µm cotton 13.5 µm 0 5 10 15 20 25 Fibre diameter (µm) Micro fibre 5.5 µm acrylic fibre 12 µm silk 12 um Superfine wool 17 µm polyester staple fibre 18.4 µm Hatcher and Bayley, 1999

12. What’s wrong with wool • Diameter – in relation to competitors • Strength – in relation to competitors

13. Tenacity (or Breaking Stress) of Apparel Fibres (N/ktex) • Merino wool 115 • Cotton 450 • Viscose 190 • Nylon 6.6 470 • Polyester 390 (normal) • Polyester 600 (high tenacity) Important across the range of industrial uses

14. What’s Wrong with Wool • Diameter – in relation to competitors • Strength – in relation to competitors • Faults • Pigmentation • Variability across seasons • Dyeing difficulties

15. Genetics

16. Genetic Improvement Programs - Current Capabilities • Dealing with traits of good heritability and phentypic variance • Have good economic information • Good performance recording and evaluation software But • L – generation interval not so hot However – focussed breeding programs make good progress

17. Why the Interest in Genes of Major effect and costly molecular tools? For dealing with particular problems : • Antagonistic correlations between fleece weight and mean fibre diameter • Fibre deficiencies – strength, diameter, pigmentation • Need for new products

18. A bit of biology

19. Wool Production - A complex system Wool Weight Fibre length Fibre diameter Muscle growth Adiposity Reproduction Milk production Basal Metabolism etc Follicle density, distribution & shape Nutrient supply/follicle Follicle branching P and S follicle initiation Nutrient Pools Adult skin Feed Intake Foetal skin I. R. Franklin

20. Morphology of Skin and Wool fibres Basic units:

21. Follicle Theories Basis for control of follicle initiation, follicle density and consequent fibre attributes • Competition between wool follicles • Biochemical pattern-forming mechanism -Reaction-Diffusion Theory • Competition for limited pool of dermal papilla cells

23. The Upshot of all this • QTL will not necessarily reflect the genetic relationships seen at the population level Eg i) locus affecting follicle initiation ii) locus affecting feed intake Fleece weight Follicle density Mean fibre diameter Fleece weight Follicle density Mean fibre diameter # Important in assessing value of some QTL

24. Known Genes of Major Effect • 1. Pigmentation Genes Courtesy of SUL

25. Pigmentation generally: • Most studied of all attributes of sheep • Effects are profound and well characterised at the phenotypic level • But • Not as simple as meets the eye

26. Self-colour black • Recessive gene, frequency in Aus. Merino flock ~5% • Approx 1 in 10 animals are carriers • Thought to be the “Agouti” locus • Agouti believed to be on sheep chromosome 13 • A test for the “black” gene would be useful to the industry, especially for testing sires.

27. Melanogenesis Agouti

28. Agouti • One of main determinants of sheep colour • many allelic variants • a wide range of effects in most species of animals

29. The Agouti gene 5bp deletion Exon 1 Exon 2 Exon 3 Exon 4 Deletion mapped in CSIRO mapping flock

30. Wool Quality Genes • N-type Gene (Halo-hair 1) • Mutation causing extreme hairiness (medullation) – incomplete dominance to wild type • Pleitropic effects on follicle morphology And horn formation

31. Halo-hair genes • Two other alleles cause similar medullation effects plus a different locus which is recessive also has similar effects • Utilisation of these genes led to development of carpet wool breeds • Tukidale, Carpetmaster, Elliottdale

32. Wool Quality Genes • Lustre • Dominant mutation • Causes high lustre lack of crimp, and sometimes a degree of yellowing • Very low frequency in most breeds of sheep Pleiotropic effects – reduced follicle density and fleece weight • Silky • Similar effect to the Lustre mutation Pleitropic effects – primary follicles in homozygotes are degenerate

33. Wool Quality Genes • Hairless • Mendelian recessive gene causing complete or partial absence of fibre at birth (hypotrichosis) • Poll Dorset breed in Australia • Valle del Belice breed in Sicily • PCR-SSCP test developed to detect the allele responsible for the hypotrichosis phenotype. • Finocchiaro et al., (2003) also postulate that the hr gene product may play a role in cell proliferation, differentiation and apoptosis in hair follicles as well as in the interfollicular epidermis.

34. Keratin Genes • Keratins are major component of wool • Keratin intermediate (IF) proteins • Keratin-associated proteins (KAP)

35. Expression of Hair Keratin Genes • Sequential and spatial patterns Courtesy of woolwise.com.au Barry Powell & Simon Bawden

36. Mouse Human Cattle Sheep 11 17 19 11 Hox-2 q21 q17 Rar-  Keratin type I IF Keratin type I IF q21 q16 q25 KAP1 genes Wnt-3 KAP2 genes q21 Growth Hormone q22 q25 q26 Mouse Human Cattle Sheep 15 12 5 3 Hox-3 q14 q14  Rar- Keratin type II IF Keratin type II IF q14 q14 KAP genes ? Wnt-1 Comparative Chromosomal Localisations of Keratin Genes Courtesy of woolwise.com.au Barry Powell & Simon Bawden

37. KAP Gene Organization • ~12 gene families • Genes within a family are clustered • Known locations: • Chr 1 - KAP 7, 8 & 6 family (?) • Chr 11 - KAP1 & 2 families, linked to IF type I locus • Chr 11 (Human) - KAP5 family • Unknown: • KAP3, 4, 9, 10, 11 & 12 families Barry Powell & Simon Bawden

39. Linkage Mapping Studies • Resources for mapping linkage between chromosomal regions and phenotype are very expensive; • At least 9 sheep flocks been set up to map chromosome regions; • All sheep grow wool • Is this a blessing or not?

40. Trait Analysis Breeds Position Marker 1. Fibre diameter Candidate gene approach Peppin Merino Chromosome 1 KRTAP6 and KRTAP8 2. Fibre diameter Genome screen Merino x Romney Linked, but not named 3. Fibre diameter Segment mapping approach INRA 401 Chromosome 6 Chromosome 25 Segment OARAE101 (20cM) Segment IDVGA8 to midpoint with IDVGA088 Putative QTL

41. Putative QTL • Other attributes: • Staple length • Staple strength • CV of fibre diameter • Crimp frequency

42. CSIRO Mapping Flock

43. Structure of CSIRO Mapping Flock

44. Phenotyping

45. Main effect(s) LOD score Comments (Merino vs Romney)† Mean fibre diameter (µm) and staple strength (N/Kt) 3.2, 3.2 Reduced mean fibre diameter, increased staple strength Primary follicle fibre diameter(µm), staple strength (N/Kt) 3.6, 3.4 Reduced primary fibre diameter, increased staple strength Clean fleece weight (kg), staple length (mm) 3.3, (2.6) Reduced clean fleece weight, staple length, increased density Clean fleece weight (kg), staple length (mm) 3.3, 3.5 Reduced clean fleece weight, staple length, and micron: multiple QTL? Mean fibre diameter (µm) 2.9 Reduced mean fibre diameter Possible QTL Identified

46. Secondary follicle density, secondary to primary follicle ratio 3.4 Increased secondary density and SP ratio, reduced mean fibre diameter and staple length Staple strength (N/Kt) 2.5 Increased staple strength (both adult and hogget) Primary follicle density, staple strength (N/Kt) 2.6, 2.9 Increased primary follicle density, reduced staple strength Resistance to compression 4.4 Increased resistance to compression Staple length/fibre diameter2 3.2 Increased length, increased micron, reduced L/D2 Mean fibre diameter (µm) 2.9 Reduced mean fibre diameter Possible QTL identified

47. Where to from here • Diameter – in relation to competitors • Fleece weight /fibre diameter antagonism • Strength – in relation to competitors • Faults • Pigmentation • Variability across seasons • Dying difficulties

48. Opportunities and Needs • Wool industry is small in comparison to meat • Need high level of collaboration and organisation • Consortium (SGI) being formed in Australia

49. Opportunities • Uncovering hidden genetic variation

50. Opportunities • Introgression • Novel combinations