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The scurs inheritance: new insights from the French Charolais breed.

Capitan A, Grohs C, Gautier M, Eggen A - BMC Genet. (2009)

Bottom Line: However, some cattle are neither polled nor horned but have so-called scurs on their heads, which are corneous growths loosely attached to the skull.Crossbreeding involving the Charolais breed and other breeds gave results similar to those reported in the Hereford breed.Our results suggest the existence of unknown genetics factors modifying the expression of the scurs locus in double heterozygous Hereford and Angus males.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UMR 1313 Génétique Animale et Biologie Intégrative, F-78350 Jouy-en-Josas, France. aurelien.capitan@jouy.inra.fr

ABSTRACT

Background: Polled animals are valued in cattle industry because the absence of horns has a significant economic impact. However, some cattle are neither polled nor horned but have so-called scurs on their heads, which are corneous growths loosely attached to the skull. A better understanding of the genetic determinism of the scurs phenotype would help to fine map the polled locus. To date, only one study has attempted to map the scurs locus in cattle. Here, we have investigated the inheritance of the scurs phenotype in the French Charolais breed and examined whether the previously proposed localisation of the scurs locus on bovine chromosome 19 could be confirmed or not.

Results: Our results indicate that the inheritance pattern of the scurs phenotype in the French Charolais breed is autosomal recessive with complete penetrance in both sexes, which is different from what is reported for other breeds. The frequency of the scurs allele (Sc) reaches 69.9% in the French Charolais population. Eleven microsatellite markers on bovine chromosome 19 were genotyped in 267 offspring (33 half-sib and full-sib families). Both non-parametric and parametric linkage analyses suggest that in the French Charolais population the scurs locus may not map to the previously identified region. A new analysis of an Angus-Hereford and Hereford-Hereford pedigree published in 1978 enabled us to calculate the frequency of the Sc allele in the Hereford breed (89.4%) and to study the penetrance of this allele in males heterozygous for both polled and scurs loci (40%). This led us to revise the inheritance pattern of the scurs phenotype proposed for the Hereford breed and to suggest that allele Sc is not fully but partially dominant in double heterozygous males while it is always recessive in females. Crossbreeding involving the Charolais breed and other breeds gave results similar to those reported in the Hereford breed.

Conclusion: Our results suggest the existence of unknown genetics factors modifying the expression of the scurs locus in double heterozygous Hereford and Angus males. The specific inheritance pattern of the scurs locus in the French Charolais breed represents an opportunity to map this gene and to identify the molecular mechanisms regulating the growth of horns in cattle.

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Pedigree of the six sires from the FPCP nucleus. The pedigree was designed using PEDIGRAPH 2.3 software [25]. Lines are drawn in different colours to better visualize the relationships between individuals.
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Figure 1: Pedigree of the six sires from the FPCP nucleus. The pedigree was designed using PEDIGRAPH 2.3 software [25]. Lines are drawn in different colours to better visualize the relationships between individuals.

Mentions: i) According to this model, non-scurred P/p bulls are supposed to be sc/sc at the scurs locus. For this reason, they cannot have sired scurred P/p daughters since only P/p Sc/Sc females would be scurred. However, in our design this is the case for no less than five NS P/p bulls. Hence, these bulls must have one Sc allele, which they transmit to their progeny without expressing the scurs phenotype themselves. Among these bulls, sires 5944, 9952, 20433 and 20434 confirm this conclusion because born to a scurred mother (assumed to be P/p Sc/Sc), they have received at least one Sc allele (Figure 1). Thus, we have assumed that these five bulls are P/p Sc/sc.


The scurs inheritance: new insights from the French Charolais breed.

Capitan A, Grohs C, Gautier M, Eggen A - BMC Genet. (2009)

Pedigree of the six sires from the FPCP nucleus. The pedigree was designed using PEDIGRAPH 2.3 software [25]. Lines are drawn in different colours to better visualize the relationships between individuals.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2719667&req=5

Figure 1: Pedigree of the six sires from the FPCP nucleus. The pedigree was designed using PEDIGRAPH 2.3 software [25]. Lines are drawn in different colours to better visualize the relationships between individuals.
Mentions: i) According to this model, non-scurred P/p bulls are supposed to be sc/sc at the scurs locus. For this reason, they cannot have sired scurred P/p daughters since only P/p Sc/Sc females would be scurred. However, in our design this is the case for no less than five NS P/p bulls. Hence, these bulls must have one Sc allele, which they transmit to their progeny without expressing the scurs phenotype themselves. Among these bulls, sires 5944, 9952, 20433 and 20434 confirm this conclusion because born to a scurred mother (assumed to be P/p Sc/Sc), they have received at least one Sc allele (Figure 1). Thus, we have assumed that these five bulls are P/p Sc/sc.

Bottom Line: However, some cattle are neither polled nor horned but have so-called scurs on their heads, which are corneous growths loosely attached to the skull.Crossbreeding involving the Charolais breed and other breeds gave results similar to those reported in the Hereford breed.Our results suggest the existence of unknown genetics factors modifying the expression of the scurs locus in double heterozygous Hereford and Angus males.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UMR 1313 Génétique Animale et Biologie Intégrative, F-78350 Jouy-en-Josas, France. aurelien.capitan@jouy.inra.fr

ABSTRACT

Background: Polled animals are valued in cattle industry because the absence of horns has a significant economic impact. However, some cattle are neither polled nor horned but have so-called scurs on their heads, which are corneous growths loosely attached to the skull. A better understanding of the genetic determinism of the scurs phenotype would help to fine map the polled locus. To date, only one study has attempted to map the scurs locus in cattle. Here, we have investigated the inheritance of the scurs phenotype in the French Charolais breed and examined whether the previously proposed localisation of the scurs locus on bovine chromosome 19 could be confirmed or not.

Results: Our results indicate that the inheritance pattern of the scurs phenotype in the French Charolais breed is autosomal recessive with complete penetrance in both sexes, which is different from what is reported for other breeds. The frequency of the scurs allele (Sc) reaches 69.9% in the French Charolais population. Eleven microsatellite markers on bovine chromosome 19 were genotyped in 267 offspring (33 half-sib and full-sib families). Both non-parametric and parametric linkage analyses suggest that in the French Charolais population the scurs locus may not map to the previously identified region. A new analysis of an Angus-Hereford and Hereford-Hereford pedigree published in 1978 enabled us to calculate the frequency of the Sc allele in the Hereford breed (89.4%) and to study the penetrance of this allele in males heterozygous for both polled and scurs loci (40%). This led us to revise the inheritance pattern of the scurs phenotype proposed for the Hereford breed and to suggest that allele Sc is not fully but partially dominant in double heterozygous males while it is always recessive in females. Crossbreeding involving the Charolais breed and other breeds gave results similar to those reported in the Hereford breed.

Conclusion: Our results suggest the existence of unknown genetics factors modifying the expression of the scurs locus in double heterozygous Hereford and Angus males. The specific inheritance pattern of the scurs locus in the French Charolais breed represents an opportunity to map this gene and to identify the molecular mechanisms regulating the growth of horns in cattle.

Show MeSH
Related in: MedlinePlus