OMIA:001354-9940 : Muscular hypertrophy (double muscling), Callipyge in Ovis aries (sheep)

Categories: Muscle phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 176290 (gene) , 613648 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2002

Cross-species summary: Abnormal increase in muscular tissue caused entirely by enlargement of existing cells (in contrast to muscular hyperplasia, in which the abnormal increase in muscular tissue is due to the formation and growth of new, normal muscle cells)

Species-specific name: Callipyge

Species-specific symbol: CLPG

Species-specific description: This trait was first reported in sheep by Cockett et al. (1994), who showed that the locus at which this potentially advantageous mutation occurred is on chromosome 18, near the non-centromeric end. The mutant allele leads to increased protein synthesis and decreased protein degradation. The practical effects include higher dressing percentage, reduced fat thickness, and reduced marbling, while carcass weight is not affected (Koohmaraie et al., 1995; 1996; Carpenter et al., 1996). Overall, callipyge lambs have a distinct advantage in retail yield and carcass conformation (Jackson et al., 1997b), with the increased muscle mass being concentrated in the leg and loin (Jackson et al., 1997c). Jackson et al. (1997a) showed that callipyge lambs have a lower feed intake than non-callipyge lambs, but the same growth rate. Consequently, callipyge lambs have a superior feed efficiency. Greasy fleece weight and staple length of callipyge lambs were slightly lower.

History: The trait was first observed in 1983 by a sheep producer who noticed a Rambouillet ram with extreme muscling (Cockett et al., 1994). After showing via breeding experiments that this trait is single-locus autosomal, Cockett et al. (1994) proposed the name "callipyge (from Greek calli-, beautiful; -pyge buttocks)" and the symbol CLPG.

Inheritance: A distinctive feature of this type of muscular hypertrophy is its unusual mode of inheritance: the only animals with the phenotype are heterozygotes who inherited the mutant allele from their sire. Cockett et al. (1996) suggested the term polar overdominance for this form of inheritance, which is likely to be the result of a form of imprinting.

Mapping: In the absence of any useful sheep markers, Cockett et al. (1994) conducted a "genome scan" with just four(!) bovine minisatellites (VNTRs), two of which had no known bovine map location, the other two of which were known to be located on bovine chromosomes BTA21 and BTA26. To the authors' understandable surprise (not to mention extraordinary luck), the BTA21 marker (GMBT16) showed linkage with the CLPG locus! Linkage analysis in additional families confirmed that GMBT16 is linked to CLPG with theta = 20%. Since GMBT16 had also been ISH-mapped to the pro-terminal region of sheep homologous chromosome OVA18, Cockett et al. (1994) had succeeded in mapping the CLPG locus! The same authors then used bovine microsatellites and additional bovine minisatellites, all known to be on BTA21, to fine-map the CPLG locus to within 3 cM of bovine microsatellite CSSM18 on OVA18. Freking et al. (1998) confirmed the map location of CLPG in a resource flock derived from Dorset rams and Romanov ewes. Extensive fine-mapping effort in the following years finally yielded two ovine BACs and a connecting PCR product that together spanned a 250kb region including the CLPG locus (Charlier et al. (2001). Sequencing of this region revealed six imprinted transcripts: "DLK1, DAT, and PEG11 were shown to be paternally expressed and GTL2, antiPEG11, and MEG8 to be maternally expressed". Four of these (PEG11, MEG8, asDAT and antiPEG11) were novel genes.

Markers: The gene is located between two microsatellite markers; 12 cM from one and 19cM from the other (Shay et al., 1998)

Molecular basis: Sequencing within the refined candidate region (described in the Mapping section above) enabled Freking et al. (2002) to identify the causative mutation as a "a single A/G polymorphism located at position 103,894 of GenBank AF354168 and position 267 of the GenBank STS AF401294". A few months later, Smit et al. (2003), working on in an independent sheep resource, identified the same mutation, which they described as "an A-to-G transition in a highly conserved dodecamer motif between DLK1 and GTL2". By 2010, knowledge of this most unusual mutant could be summarised as follows. "The mutation is a base substitution in a non-coding section of a 90-kb region of DNA that contains six genes: DLK1, DAT, and PEG11 have paternal allele-specific expression whereas GTL2, PEG11AS and MEG8 are expressed from the maternal allele. When an animal inherits the callipyge mutation from its sire but not its dam, the mutation increases the expression of the DLK1 and PEG11 genes on the same (paternal) chromosome; the mutation is said to be cis-acting. The increased expression of these two genes is associated with the muscle hypertrophy of the callipyge trait." (Nicholas, 2010; Introduction to Veterinary Genetics, Wiley-Blackwell, Oxford; p. 202)

Breed: Rambouillet (Sheep) (VBO_0001570).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
DLK1 delta-like 1 homolog (Drosophila) Ovis aries - no genomic information (-..-) DLK1 Homologene, Ensembl , NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
914 Rambouillet (Sheep) Muscular hypertrophy (double muscling), Callipyge DLK1 regulatory Naturally occurring variant Oar_rambouillet_v1.0 18 g.66187430A>G "a single A/G polymorphism located at position 103,894 of GenBank AF354168 and position 267 of the GenBank STS AF401294" (Freking et al., 2002) "the CLPG mutation, an A to G transition in a highly conserved dodecamer motif located in the 90-Kb intergenic region separating the Delta-like 1 homologue (DLK1) and Gene trap locus 2 (GTL2) genes in the eponymous imprinted domain" (Xu et al., 2015; PubMed 26474044) In relation to the Oar_v4.0/oviAri4 genome assembly, the location of the causative SNP is OAR18:g.64294536A>G (Ross Tellam, pers. comm. to FN 5 Nov 2020) rs10721113 2002 12368241 The genomic location on Oar_rambouillet_v1.0 was determined by Katie Eager & Shernae Woolley, EMAI, NSW Department of Primary Industries.

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2024). OMIA:001354-9940: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2024 Hubert, J.N., Perret, M., Riquet, J., Demars, J. :
Livestock species as emerging models for genomic imprinting. Front Cell Dev Biol 12:1348036, 2024. Pubmed reference: 38500688. DOI: 10.3389/fcell.2024.1348036.
2022 Wang, J.T., Wang, G.S., Gong, Y.F., Qiao, X., Li, X., Wang, G.Z., Zheng, Y.Z., Lv, J.G., Li, X.L., Liu, Z.Z. :
Screening of three-way crossbred combination and genetic effect analysis of the SNP in the <i>CLPG</i> gene in meat sheep. Arch Anim Breed 65:417-426, 2022. Pubmed reference: 36756164. DOI: 10.5194/aab-65-417-2022.
2021 Derks, M.F.L., Steensma, M. :
Review: Balancing selection for deleterious alleles in livestock. Front Genet 12:761728, 2021. Pubmed reference: 34925454. DOI: 10.3389/fgene.2021.761728.
2020 Gorlov, I.F., Shirokova, N.V., Kolosov, Y.A., Kolosov, A.Y., Getmantseva, L.V., Slozhenkina, M.I., Mosolova, N.I., Anisimova, E.Y., Ponomariov, V.V. :
Polymorphism of <i>CLPG</i> gene in three sheep breeds grown in the steppe zone of the Russian Federation. J Adv Vet Anim Res 7:51-55, 2020. Pubmed reference: 32219109. DOI: 10.5455/javar.2020.g392.
Ma, D., Yu, Q., Hedrick, V.E., Cooper, B.R., Paschoal Sobreira, T.J., Oh, J.H., Chun, H., Kim, Y.H.B. :
Proteomic and metabolomic profiling reveals the involvement of apoptosis in meat quality characteristics of ovine M. longissimus from different callipyge genotypes. Meat Sci 166:108140, 2020. Pubmed reference: 32298943. DOI: 10.1016/j.meatsci.2020.108140.
2019 Jawasreh, K.I., Alamareen, A.H., Obeidat, M.D., Aad, P.Y. :
Growth Performance and Meat Characteristics of the First Awassi-Rambouillet Callipyge Backcross. Animals (Basel) 9, 2019. Pubmed reference: 31374974. DOI: 10.3390/ani9080517.
Jawasreh, K.I.Z., Al-Amareen, A.H., Aad, P.Y. :
Growth performance and meat characteristics of the first filial Awassi-Rambouillet callipyge ram lambs. Vet World 12:783-788, 2019. Pubmed reference: 31439994. DOI: 10.14202/vetworld.2019.783-788.
2018 Cramer, T., Penick, M.L., Waddell, J.N., Bidwell, C.A., Kim, Y.H.B. :
A new insight into meat toughness of callipyge lamb loins - The relevance of anti-apoptotic systems to decreased proteolysis. Meat Sci 140:66-71, 2018. Pubmed reference: 29533813. DOI: 10.1016/j.meatsci.2018.03.002.
Freking, B.A., King, D.A., Shackelford, S.D., Wheeler, T.L., Smith, T.P.L. :
Effects and interactions of myostatin and callipyge mutations: I. Growth and carcass traits. J Anim Sci 96:454-461, 2018. Pubmed reference: 29401324. DOI: 10.1093/jas/skx055.
Mikovic, J., Sadler, K., Butchart, L., Voisin, S., Gerlinger-Romero, F., Della Gatta, P., Grounds, M.D., Lamon, S. :
MicroRNA and Long Non-coding RNA Regulation in Skeletal Muscle From Growth to Old Age Shows Striking Dysregulation of the Callipyge Locus. Front Genet 9:548, 2018. Pubmed reference: 30505320. DOI: 10.3389/fgene.2018.00548.
Yu, H., Waddell, J.N., Kuang, S., Tellam, R.L., Cockett, N.E., Bidwell, C.A. :
Identification of genes directly responding to DLK1 signaling in Callipyge sheep. BMC Genomics 19:283, 2018. Pubmed reference: 29690867. DOI: 10.1186/s12864-018-4682-1.
2015 Gao, Y.Q., Chen, X., Wang, P., Lu, L., Zhao, W., Chen, C., Chen, C.P., Tao, T., Sun, J., Zheng, Y.Y., Du, J., Li, C.J., Gan, Z.J., Gao, X., Chen, H.Q., Zhu, M.S. :
Regulation of DLK1 by the maternally expressed miR-379/miR-544 cluster may underlie callipyge polar overdominance inheritance. Proc Natl Acad Sci U S A 112:13627-32, 2015. Pubmed reference: 26487685. DOI: 10.1073/pnas.1511448112.
Xu, X., Ectors, F., Davis, E.E., Pirottin, D., Cheng, H., Farnir, F., Hadfield, T., Cockett, N., Charlier, C., Georges, M., Takeda, H. :
Ectopic Expression of Retrotransposon-Derived PEG11/RTL1 Contributes to the Callipyge Muscular Hypertrophy. PLoS One 10:e0140594, 2015. Pubmed reference: 26474044. DOI: 10.1371/journal.pone.0140594.
2014 Bidwell, C.A., Waddell, J.N., Taxis, T.M., Yu, H., Tellam, R.L., Neary, M.K., Cockett, N.E. :
New insights into polar overdominance in callipyge sheep. Anim Genet 45 Suppl 1:51-61, 2014. Pubmed reference: 24990181. DOI: 10.1111/age.12132.
Cheng, H., Xu, X., Hadfield, T., Cockett, N., Charlier, C., Georges, M., Takeda, H. :
Experimental evaluation does not reveal a direct effect of microRNA from the callipyge locus on DLK1 expression. BMC Genomics 15:944, 2014. Pubmed reference: 25359221. DOI: 10.1186/1471-2164-15-944.
Li, J., Greenwood, P.L., Cockett, N.E., Hadfield, T.S., Vuocolo, T., Byrne, K., White, J.D., Tellam, R.L., Schirra, H.J. :
Impacts of the Callipyge mutation on ovine plasma metabolites and muscle fibre type. PLoS One 9:e99726, 2014. Pubmed reference: 24937646. DOI: 10.1371/journal.pone.0099726.
2012 Bi, P., Kuang, S. :
Meat Science and Muscle Biology Symposium: stem cell niche and postnatal muscle growth. J Anim Sci 90:924-35, 2012. Pubmed reference: 22100594. DOI: 10.2527/jas.2011-4594.
Sun, W., Hudson, N.J., Reverter, A., Waardenberg, A.J., Tellam, R.L., Vuocolo, T., Byrne, K., Dalrymple, B.P. :
An Always Correlated gene expression landscape for ovine skeletal muscle, lessons learnt from comparison with an "equivalent" bovine landscape. BMC Res Notes 5:632, 2012. Pubmed reference: 23148653. DOI: 10.1186/1756-0500-5-632.
Tellam, R.L., Cockett, N.E., Vuocolo, T., Bidwell, C.A. :
Genes contributing to genetic variation of muscling in sheep. Front Genet 3:164, 2012. Pubmed reference: 22952470. DOI: 10.3389/fgene.2012.00164.
2010 Byrne, K., Colgrave, ML., Vuocolo, T., Pearson, R., Bidwell, CA., Cockett, NE., Lynn, DJ., Fleming-Waddell, JN., Tellam, RL. :
The imprinted retrotransposon-like gene PEG11 (RTL1) is expressed as a full-length protein in skeletal muscle from Callipyge sheep. PLoS One 5:e8638, 2010. Pubmed reference: 19380578. DOI: 10.1074/jbc.M109.000299.
Caiment, F., Charlier, C., Hadfield, T., Cockett, N., Georges, M., Baurain, D. :
Assessing the effect of the CLPG mutation on the microRNA catalog of skeletal muscle using high-throughput sequencing. Genome Res 20:1651-62, 2010. Pubmed reference: 20944086. DOI: 10.1101/gr.108787.110.
Everts, AK., Wulf, DM., Wheeler, TL., Everts, AJ., Weaver, AD., Daniel, JA. :
Enhancement Technology Improves Palatability of Normal and Callipyge Lamb. J Anim Sci , 2010. Pubmed reference: 20675603. DOI: 10.2527/jas.2010-2845.
Warner, RD., Greenwood, PL., Pethick, DW., Ferguson, DM. :
Genetic and environmental effects on meat quality. Meat Sci 86:171-83, 2010. Pubmed reference: 20561754. DOI: 10.1016/j.meatsci.2010.04.042.
2009 Fleming-Waddell, J.N., Olbricht, G.R., Taxis, T.M., White, J.D., Vuocolo, T., Craig, B.A., Tellam, R.L., Neary, M.K., Cockett, N.E., Bidwell, C.A. :
Effect of DLK1 and RTL1 but not MEG3 or MEG8 on muscle gene expression in Callipyge lambs. PLoS One 4:e7399, 2009. Pubmed reference: 19816583. DOI: 10.1371/journal.pone.0007399.
Fleming-Waddell, JN., Olbricht, GR., Taxis, TM., White, JD., Vuocolo, T., Craig, BA., Tellam, RL., Neary, MK., Cockett, NE., Bidwell, CA. :
Effect of DLK1 and RTL1 but not MEG3 or MEG8 on muscle gene expression in Callipyge lambs. PLoS One 4:e7399, 2009. Pubmed reference: 8943082.
Kemp, CM., King, DA., Shackelford, SD., Wheeler, TL., Koohmaraie, M. :
The caspase proteolytic system in callipyge and normal lambs in longissimus, semimembranosus, and infraspinatus muscles during postmortem storage. J Anim Sci , 2009. Pubmed reference: 19420232. DOI: 10.2527/jas.2009-1790.
2008 Lavulo, LT., Uaesoontrachoon, K., Mirams, M., White, JD., Cockett, NE., Mackie, EJ., Pagel, CN. :
Myoblasts isolated from hypertrophy-responsive callipyge muscles show altered growth rates and increased resistance to serum deprivation-induced apoptosis. Cells Tissues Organs 187:141-51, 2008. Pubmed reference: 17957094. DOI: 10.1159/000110080.
White, JD., Vuocolo, T., McDonagh, M., Grounds, MD., Harper, GS., Cockett, NE., Tellam, R. :
Analysis of the callipyge phenotype through skeletal muscle development; association of Dlk1 with muscle precursor cells. Differentiation 76:283-98, 2008. Pubmed reference: 17697128. DOI: 10.1111/j.1432-0436.2007.00208.x.
2007 Fleming-Waddell, JN., Wilson, LM., Olbricht, GR., Vuocolo, T., Byrne, K., Craig, BA., Tellam, RL., Cockett, NE., Bidwell, CA. :
Analysis of gene expression during the onset of muscle hypertrophy in callipyge lambs. Anim Genet 38:28-36, 2007. Pubmed reference: 17257185. DOI: 10.1111/j.1365-2052.2006.01562.x.
Vuocolo, T., Byrne, K., White, J., McWilliam, S., Reverter, A., Cockett, NE., Tellam, RL. :
Identification of a gene network contributing to hypertrophy in callipyge skeletal muscle. Physiol Genomics 28:253-72, 2007. Pubmed reference: 17077277. DOI: 10.1152/physiolgenomics.00121.2006.
2006 Freking, BA., Leymaster, KA. :
Evaluation of the ovine callipyge locus: IV. Genotypic effects on reproductive traits. J Anim Sci 84:311-6, 2006. Pubmed reference: 16424258.
Isler, BJ., Freking, BA., Thallman, RM., Heaton, MP., Leymaster, KA. :
Evaluation of associations between prion haplotypes and growth, carcass, and meat quality traits in a Dorset x Romanov sheep population. J Anim Sci 84:783-8, 2006. Pubmed reference: 16543554.
Liu, GQ., Dai, R., Ren, HX., Wang, XH., Liu, SR., Sun, YL., Yang, LG. :
[Polymorphism analysis of genes associated with hindquarters muscular development on chromosome 18 in Xinjiang meat sheep] Yi Chuan 28:815-20, 2006. Pubmed reference: 16825168.
McKeown, B., Rowan, P., Sung, R., Derbyshire, R. :
Intramolecular controls for the generation of clinical-quality SNP genotypes and the assessment of normal heterozygote imbalance. Electrophoresis 27:1725-31, 2006. Pubmed reference: 16645948. DOI: 10.1002/elps.200500015.
Murphy, SK., Nolan, CM., Huang, Z., Kucera, KS., Freking, BA., Smith, TP., Leymaster, KA., Weidman, JR., Jirtle, RL. :
Callipyge mutation affects gene expression in cis: A potential role for chromatin structure. Genome Res 16:340-346, 2006. Pubmed reference: 16415109. DOI: 10.1101/gr.4389306.
Perkins, AC., Kramer, LN., Spurlock, DM., Hadfield, TS., Cockett, NE., Bidwell, CA. :
Postnatal changes in the expression of genes located in the callipyge region in sheep skeletal muscle. Anim Genet 37:535-42, 2006. Pubmed reference: 17121598. DOI: 10.1111/j.1365-2052.2006.01518.x.
Ren, H.X., Dai, R., Zhang, X.G., Liu, G.Q., Wang, X.H., Shi, G.Q., Liu, S.R., Gui, D.C., Lü, G.R. :
[Relationship between microsatellite DNA polymorphism and hind-quarter development in sheep chromosome 18]. Yi Chuan 28:1525-31, 2006. Pubmed reference: 17138538.
Takeda, H., Caiment, F., Smit, M., Hiard, S., Tordoir, X., Cockett, N., Georges, M., Charlier, C. :
The callipyge mutation enhances bidirectional long-range DLK1-GTL2 intergenic transcription in cis. Proc Natl Acad Sci U S A 103:8119-24, 2006. Pubmed reference: 16690740. DOI: 10.1073/pnas.0602844103.
2005 Cockett, NE., Smit, MA., Bidwell, CA., Segers, K., Hadfield, TL., Snowder, GD., Georges, M., Charlier, C. :
The callipyge mutation and other genes that affect muscle hypertrophy in sheep. Genet Sel Evol 37 Suppl 1:S65-81, 2005. Pubmed reference: 15601596. DOI: 10.1051/gse:2004032.
Davis, E., Caiment, F., Tordoir, X., Cavaille, J., Ferguson-Smith, A., Cockett, N., Georges, M., Charlier, C. :
RNAi-mediated allelic trans-interaction at the imprinted Rtl1/Peg11 locus. Current Biology 15:743-9, 2005. Pubmed reference: 15854907. DOI: 10.1016/j.cub.2005.02.060.
Lewis, A., Redrup, L. :
Genetic imprinting: conflict at the Callipyge locus. Curr Biol 15:R291-4, 2005. Pubmed reference: 15854893. DOI: 10.1016/j.cub.2005.04.003.
Murphy, SK., Freking, BA., Smith, TP., Leymaster, K., Nolan, CM., Wylie, AA., Evans, HK., Jirtle, RL. :
Abnormal postnatal maintenance of elevated DLK1 transcript levels in callipyge sheep. Mamm Genome 16:171-83, 2005. Pubmed reference: 15834634. DOI: 10.1007/s00335-004-2421-1.
Smit, MA., Tordoir, X., Gyapay, G., Cockett, NE., Georges, M., Charlier, C. :
BEGAIN: a novel imprinted gene that generates paternally expressed transcripts in a tissue- and promoter-specific manner in sheep. Mamm Genome 16:801-14, 2005. Pubmed reference: 16261422. DOI: 10.1007/s00335-004-2415-z.
2004 Bidwell, CA., Kramer, LN., Perkins, AC., Hadfield, TS., Moody, DE., Cockett, NE. :
Expression of PEG11 and PEG11AS transcripts in normal and callipyge sheep. BMC Biol 2:17, 2004. Pubmed reference: 15298706. DOI: 10.1186/1741-7007-2-17.
Charlier, C. :
Towards the molecular understanding of the polar overdominance phenomenon associated with the callipyge phenotype in sheep. Bull Mem Acad R Med Belg 159:490-6, 2004. Pubmed reference: 16035622.
Davis, E., Jensen, CH., Schroder, HD., Farnir, F., Shay-Hadfield, T., Kliem, A., Cockett, N., Georges, M., Charlier, C. :
Ectopic expression of DLK1 protein in skeletal muscle of padumnal heterozygotes causes the callipyge phenotype. Curr Biol 14:1858-62, 2004. Pubmed reference: 15498495. DOI: 10.1016/j.cub.2004.09.079.
Georges, M., Charlier, C., Smit, M., Davis, E., Shay, T., Tordoir, X., Takeda, H., Caiment, F., Cockett, N. :
Toward molecular understanding of polar overdominance at the ovine callipyge locus. Cold Spring Harb Symp Quant Biol 69:477-83, 2004. Pubmed reference: 16117683. DOI: 10.1101/sqb.2004.69.477.
Haig, D. :
Genomic imprinting and kinship: how good is the evidence? Annu Rev Genet 38:553-85, 2004. Pubmed reference: 15568986. DOI: 10.1146/annurev.genet.37.110801.142741.
Harper, GS., Pethick, DW. :
Fatness in production animals: using genetic and environmental levers to meet consumer demand. Asia Pac J Clin Nutr 13:S37, 2004.
Shackelford, SD., Wheeler, TL., Koohmaraie, M. :
Evaluation of sampling, cookery, and shear force protocols for objective evaluation of lamb longissimus tenderness. J Anim Sci 82:802-7, 2004. Pubmed reference: 15032437.
2003 Georges, M., Charlier, C., Cockett, N. :
The callipyge locus: evidence for the trans interaction of reciprocally imprinted genes Trends in Genetics 19:248-52, 2003. Pubmed reference: 12711215.
Kerth, CR., Jackson, SP., Ramsey, CB., Miller, MF. :
Characterization and consumer acceptance of three muscles from Hampshire x Rambouillet cross sheep expressing the callipyge phenotype. J Anim Sci 81:2213-8, 2003. Pubmed reference: 12968696.
Kuber, P.S., Duckett, S.K., Busboom, J.R., Snowder, G.D., Dodson, M.V., Vierck, J.L., Bailey, J.F. :
Measuring the effects of phenotype and mechanical restraint on proteolytic degradation and rigor shortening in callipyge lamb longissimus dorsi muscle during extended aging Meat Science 63:325-331, 2003.
Smit, M., Segers, K., Carrascosa, L.G., Shay, T., Baraldi, F., Gyapay, G., Snowder, G., Georges, M., Cockett, N., Charlier, C. :
Mosaicism of Solid Gold supports the causality of a noncoding A-to-G transition in the determinism of the callipyge phenotype Genetics 163:453-6, 2003. Pubmed reference: 12586730.
2002 Abdulkhaliq, A.M., Meyer, H.H., Thompson, J.M., Holmes, Z.A., Forsberg, N.E., Davis, S.L. :
Callipyge gene effects on lamb growth, carcass traits, muscle weights and meat characteristics Small Ruminant Research 45:89-93, 2002.
Freking, B.A., Murphy, S.K., Wylie, A.A., Rhodes, S.J., Keele, J.W., Leymaster, K.A., Jirtle, R.L., Smith, T.P.L. :
Identification of the single base change causing the callipyge muscle hypertrophy phenotype, the only known example of polar overdominance in mammals Genome Research 12:1496-1506, 2002. Pubmed reference: 12368241. DOI: 10.1101/gr.571002.
2001 Berghmans, S., Segers, K., Shay, T., Georges, M., Cockett, N., Charlier, C. :
Breakpoint mapping positions the callipyge gene within a 450-kilobase chromosome segment containing the DLK1 and GTL2 genes Mammalian Genome 12:183-185, 2001. Pubmed reference: 11210193.
Bidwell, C.A., Shay, T.L., Georges, M., Beever, J.E., Berghmans, S., Cockett, N.E. :
Differential expression of the GTL2 gene within the callipyge region of ovine chromosome 18 Animal Genetics 32:248-256, 2001. Pubmed reference: 11683710.
Charlier, C., Segers, K., Wagenaar, D., Karim, L., Berghams, S., Jaillon, O., Shay, T., Weissenbach, J., Cockett, N., Gyapay, G., Georges, M. :
Human-ovine comparative sequencing of a 250-kb imprinted domain encompassing the callipyge (clpg) locus and identification of six imprinted transcripts: DLK1, DAT, GTL2, PEG11, antiPEG11, and MEG8 Genome Research 11:850-862, 2001. Pubmed reference: 11337479. DOI: 10.1101/gr.172701.
Charlier, C., Segers, K., Karim, L., Shay, T., Gyapay, G., Cockett, N., Georges, M. :
The callipyge mutation enhances the expression of coregulated imprinted genes in cis without affecting their imprinting status Nature Genetics 27:367-369, 2001. Pubmed reference: 11279514. DOI: 10.1038/86856.
Delgado, E.F., Geesink, G.H., Marchello, J.A., Goll, D.E., Koohmaraie, M. :
Properties of myofibril-bound calpain activity in longissimus muscle of callipyge and normal sheep Journal of Animal Science 79:2097-2107, 2001. Pubmed reference: 11518218.
Delgado, E.F., Geesink, G.H., Marchello, J.A., Goll, D.E., Koohmaraie, M. :
The calpain system in three muscles of normal and callipyge sheep Journal of Animal Science 79:398-412, 2001. Pubmed reference: 11219449.
Goodson, K.J., Miller, R.K., Savell, J.W. :
Carcass traits, muscle characteristics, and palatability attributes of lambs expressing the callipyge phenotype Meat Science 58:381-387, 2001.
Shay, T.L., Berghmans, S., Segers, K., Meyers, S., Beever, J.E., Womack, J.E., Georges, M., Charlier, C., Cockett, N.E. :
Fine-mapping and construction of a bovine contig spanning the ovine callipyge locus Mammalian Genome 12:141-149, 2001. Pubmed reference: 11210184.
Wiegand, B.R., Parrish, F.C., Morrical, D.G., Huff-Lonergan, E. :
Feeding high levels of vitamin D-3 does not improve tenderness of callipyge lamb loin chops Journal of Animal Science 79:2086-2091, 2001. Pubmed reference: 11518216.
2000 Carpenter, C.E., Rodriguez, B.T., Cockett, N.E. :
Growth and differentiation of cultured satellite cells from callipyge and normal lambs Canadian Journal of Animal Science 80:297-302, 2000.
Carpenter, C.E., Cockett, N.E. :
Histology of longissimus muscle from 2-week-old and 8-week-old normal and callipyge lambs Canadian Journal of Animal Science 80:511-514, 2000.
Duckett, S.K., Snowder, G.D., Cockett, N.E. :
Effect of the callipyge gene on muscle growth, calpastatin activity, and tenderness of three muscles across the growth curve Journal of Animal Science 78:2836-2841, 2000. Pubmed reference: 11063306.
Fahrenkrug, S.C., Freking, B.A., Rexroad, C.E., Leymaster, K.A., Kappes, S.M., Smith, T.P.L. :
Comparative mapping of the ovine clpg locus Mammalian Genome 11:871-876, 2000. Pubmed reference: 11003702.
Lorenzen, C.L., Koohmaraie, M., Shackelford, S.D., Jahoor, F., Freetly, H.C., Wheeler, T.L., Savell, J.W., Fiorotto, M.L. :
Protein kinetics in callipyge lambs Journal of Animal Science 78:78-87, 2000. Pubmed reference: 10682805.
Segers, K., Vaiman, D., Berghmans, S., Shay, T., Meyers, S., Beever, J., Cockett, N., Georges, M., Charlier, C. :
Construction and characterization of an ovine BAC contig spanning the callipyge locus Animal Genetics 31:352-359, 2000. Pubmed reference: 11167521.
1999 Busboom, J.R., Wahl, T.I., Snowder, G.D. :
Economics of callipyge lamb production Journal of Animal Science 77:243-248, 1999.
Cockett, N.E., Jackson, S.P., Snowder, G.D., Shay, T.L., Berghmans, S., Beever, J.E., Carpenter, C., Georges, M. :
The callipyge phenomenon: Evidence for unusual genetic inheritance Journal of Animal Science 77:221-227, 1999.
Fahmy, M.H., Gariepy, C., Fortin, J. :
Carcass quality of crossbred lambs expressing the callipyge phenotype born to Romanov purebred and crossbred ewes Animal Science 69:525-533, 1999.
Freking, B.A., Keele, J.W., Shackelford, S.D., Wheeler, T.L., Koohmaraie, M., Nielsen, M.K., Leymaster, K.A. :
Evaluation of the ovine callipyge locus: III. Genotypic effects on meat quality traits Journal of Animal Science 77:2336-2344, 1999. Pubmed reference: 10492437.
Geesink, G.H., Koohmaraie, M. :
Postmortem proteolysis and calpain/calpastatin activity in callipyge and normal lamb biceps femoris during extended postmortem storage Journal of Animal Science 77:1490-1501, 1999. Pubmed reference: 10375226.
Kerth, C.R., Cain, T.L., Jackson, S.P., Ramsey, C.B., Miller, M.F. :
Electrical stimulation effects on tenderness of five muscles from Hampshire x Rambouillet crossbred lambs with the callipyge phenotype Journal of Animal Science 77:2951-2955, 1999. Pubmed reference: 10568463.
Lien, S., Cockett, N.E., Klungland, H., Arnheim, N., Georges, M., Gomez-Raya, L. :
High-resolution gametic map of the sheep callipyge region: linkage heterogeneity among rams detected by sperm typing Animal Genetics 30:42-46, 1999. Pubmed reference: 10050282.
Solomon, M.B. :
The callipyge phenomenon: Tenderness intervention methods Journal of Animal Science 77:238-242, 1999. Pubmed reference: 10064050.
1998 Cockett, N.E., Berghams, S., Beckers, M.-C., Shay, T.L., Jackson, S.P., Snowder, G.D., Georges, M. :
The Callipyge gene of sheep Proceedings of the 6th World Congress on Genetics Applied to Livestock Production 26:525-528, 1998.
Duckett, SK., Klein, TA., Leckie, RK., Thorngate, JH., Busboom, JR., Snowder, GD. :
Effect of freezing on calpastatin activity and tenderness of callipyge lamb. J Anim Sci 76:1869-74, 1998. Pubmed reference: 9690642.
Freking, B.A., Keele, J.W., Nielsen, M.K., Leymaster, K.A. :
Evaluation of the ovine callipyge locus - II - genotypic effects on growth, slaughter, and carcass traits Journal of Animal Science 76:2549-2559, 1998. Pubmed reference: 9814893.
Freking, B.A., Keele, J.W., Beattie, C.W., Kappes, S.M., Smith, T.P.L., Sonstegard, T.S., Nielsen, M.K., Leymaster, K.A. :
Evaluation of the ovine callipyge locus - I - relative chromosomal position and gene action Journal of Animal Science 76:2062-2071, 1998. Pubmed reference: 9734855.
Koohmaraie, M., Shackelford, S.D., Wheeler, T.L. :
Effect of prerigor freezing and postrigor calcium chloride injection on the tenderness of callipyge longissimus Journal of Animal Science 76:1427-1432, 1998. Pubmed reference: 9621949.
Shay, T.L., Garbett, C., Bottema, C.D.K., Davis, S.K., Taylor, J.F., Cockett, N.E. :
Further characterization of the callipyge region in sheep [abstract] Plant & Animal Genome VI :abstract P310, 1998.
Solomon, M.B., Carpenter, C.E., Snowder, G.D., Cockett, N.E. :
Tenderizing callipyge lamb with the hydrodyne process and electrical stimulation Journal of Muscle Foods 9:305-311, 1998.
Taylor, RG., Koohmaraie, M. :
Effects of postmortem storage on the ultrastructure of the endomysium and myofibrils in normal and callipyge longissimus. J Anim Sci 76:2811-7, 1998. Pubmed reference: 9856390.
Whisnant, C.S., Kline, R.S., Branum, J.C., Zaunbrecher, G.M., Khan, M.Z., Jackson, S.P. :
Hormonal profiles of callipyge and normal sheep Journal of Animal Science 76:1443-1447, 1998. Pubmed reference: 9621952.
1997 Clare, T.L., Jackson, S.P., Miller, M.F., Elliott, C.T., Ramsey, C.B. :
Improving tenderness of normal and callipyge lambs with calcium chloride Journal of Animal Science 75:377-385, 1997. Pubmed reference: 9051460.
Cockett, N.E., Berghams, S., Beckers, M.C., Shay, T.L., Jackson, S.P., Snowder, G.D., Georges, M. :
The callipyge gene of sheep Animal Biotechnology 8:23-30, 1997.
Jackson, S.P., Green, R.D., Miller, M.F. :
Phenotypic characterization of Rambouillet sheep expressing the callipyge gene. 1. Inheritance of the condition and production characteristics Journal of Animal Science 75:14-18, 1997. Pubmed reference: 9027543.
Jackson, S.P., Miller, M.F., Green, R.D. :
Phenotypic characterization of Rambouillet sheep expressing the callipyge gene. 3. Muscle weights and muscle weight distribution Journal of Animal Science 75:133-138, 1997. Pubmed reference: 9027558.
Jackson, S.P., Miller, M.F., Green, R.D. :
Phenotypic characterization of Rambouillet sheep expressing the callipyge gene. 2. Carcass characteristics and retail yield Journal of Animal Science 75:125-132, 1997. Pubmed reference: 9027557.
Lewis, G.S. :
Improving tenderness of normal and callipyge lambs with calcium chloride - editors comment Journal of Animal Science 75:1987-1988, 1997.
Rumsey, T.S. :
Comment on the paper "Improving tenderness of normal and callipyge lambs with calcium chloride". Journal of Animal Science 75:1987, 1997. Pubmed reference: 9222861.
Shackelford, S.D., Wheeler, T.L., Koohmaraie, M. :
Effect of the callipyge phenotype and cooking method on tenderness of several major lamb muscles Journal of Animal Science 75:2100-2105, 1997. Pubmed reference: 9263057.
1996 Carpenter, E., Rice, O.D., Cockett, N.E., Snowder, G.D. :
Histology and composition of muscles from normal and callipyge lambs Journal of Animal Science 74:388-393, 1996. Pubmed reference: 8690675.
Cockett, N.E., Jackson, S.P., Shay, T.L., Farnir, F., Berghmans, S., Snowder, G.D., Nielsen, D.M., Georges, M. :
Polar overdominance at the ovine callipyge locus Science 273:236-238, 1996. Pubmed reference: 8662506.
Field, R.A., McCormick, R.J., Brown, D.R., Hinds, F.C., Snowder, G.D. :
Collagen crosslinks in longissimus muscle from lambs expressing the callipyge gene Journal of Animal Science 74:2943-2947, 1996. Pubmed reference: 8994908.
Georges, M., Cockett, N. :
The ovine callipyge locus - a paradigm illustrating the importance of non-Mendelian genetics in livestock Reproduction, Nutrition, Development 36:651-657, 1996. Pubmed reference: 9021876.
Koohmaraie, M., Shackelford, S.D., Wheeler, T.L. :
Effects of a beta-adrenergic agonist (L-644,969) and male sex condition on muscle growth and meat quality of callipyge lambs Journal of Animal Science 74:70-79, 1996. Pubmed reference: 8778114.
Meyer, H.H., Adulkhaliq, A., Davis, S.L., Thompson, J., Nabioullin, R., Wu, P.Y., Forsberg, N.E. :
Effects of the callipyge phenotype on serum creatinine, total cholesterol, low-density lipoproteins, very-low-density lipoproteins, high-density lipoproteins, and triacylglycerol in growing lambs Journal of Animal Science 74:1548-1552, 1996. Pubmed reference: 8818799.
1995 Koohmaraie, M., Shackelford, S.D., Wheeler, T.L., Lonergan, S.M., Doumit, M.E. :
A muscle hypertrophy condition in lamb (callipyge) - characterization of effects on muscle growth and meat quality traits Journal of Animal Science 73:3596-3607, 1995. Pubmed reference: 8655433.
1994 Cockett, N.E., Jackson, S.P., Shay, T.L., Nielsen, D., Moore, S.S., Steele, M.R., Barendse, W., Green, R.D., Georges, M. :
Chromosomal Localization of the Callipyge Gene in Sheep (Ovis aries) Using Bovine DNA Markers Proceedings of the National Academy of Sciences of the United States of America 91:3019-3023, 1994. Pubmed reference: 8159698.

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  • Created by Frank Nicholas on 22 Aug 2006
  • Changed by Frank Nicholas on 19 Sep 2011
  • Changed by Frank Nicholas on 09 Dec 2011
  • Changed by Frank Nicholas on 21 Sep 2012
  • Changed by Imke Tammen2 on 20 Feb 2023
  • Changed by Imke Tammen2 on 18 Jun 2024