C. LaMarsh

DP Sponenberg

Genetics Selection Evolution

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Dominant and recessive brown in goats
DP Sponenberg1 C LaMarsh2
1 Virginia-Maryland Regional College of Veterinary Medicine,
Virginia Tech, Blacksburg, VA 24061;
2 Blue Berry Sunrise Farm Pygmy Goats, 14453 S Macksburg Rd,
Molalla, OR 97038, USA
(Received 2 May 1995; accepted 18 October 1995)
Summary - Pygmy goats in the USA occur in a variety of colors including black, roan
(called agouti by breeders), and badgerface. In a minority of animals the black areas are
replaced by dark brown or medium brown. The colors of kids from matings among black,
dark-brown, and medium-brown goats were observed. The results are consistent with three
alleles at the Brown locus: dark brown (Bd) dominant to wild type (B+) which is dominant
to medium brown Bb).
goat / genetics / coat color / brown / Pygmy goat
Résumé - Bruns dominant et récessif chez la chèvre. Les chèvres Pygmy des États
Unis présentent une variété de couleurs comprenant le noir, le rouan (appelé agouti par
les éleveurs), et « face de blaireau» («badger face»). Chez quelques animaux les zones
noires sont remplacées par du brun foncé ou du brun moyen. On a observé des chevreaux
issus de croisements entre des parents noirs, brun foncé ou brun moyen. Les résultats sont
en accord avec l’existence de trois allèles au locus Brun: le brun foncé (Nd) dominant sur
le type sauvage (B+) lui-même dominant sur le brun moyen (Bb).
chèvre / génétique / couleur de robe / brun / chèvre Pygmy
INTRODUCTION
Inheritance of coat color in goats has received less attention than has that of sheep,
primarily due to the economic importance of white sheep’s wool and lack of a
similar importance for color in most goats. Recent work (Adalsteinsson et al, 1994)
has documented the similarity of the genetic control of many goat colors to sheep
colors.
The relationship of brown to black eumelanin in goats is one aspect of color
genetics that has been studied repeatedly with conflicting results. Early works
include those of Asdell and Buchanan Smith (1928) and Eidregevic (1941), who
concluded that brown was dominant to black. This was further substantiated by
Hards (1950). Lauvergne and Howell (1978) postulate that both brown and light
brown are recessive to black, but segregation data were not available for analysis.
Adalsteinsson et al (1994) conclude that light brown, typical of the Toggenburg
breed, is dominant to black. The general conclusion one can draw from past work
is that brown is dominant to black, and that this brown is the light brown of
the Toggenburg breed. Other types of brown have been less well documented by
segregation data.
Two types of brown are present in the Pygmy goat breed in the USA. That
these are eumelanic is substantiated by the fact that each of these browns is seen
in conjunction with the badgerface pattern (termed caramel in this breed) in which
the browns replace black in the typical pattern. These two types of brown are
distinct, and are easily recognized by breeders. One is a dark brown, and is often
called cocoa brown by breeders. This is a very dark brown. The other is a medium
brown which is much lighter and brighter than the dark brown, and is termed red
by breeders even though it is an eumelanic phenomenon, and not pheomelanic as
are most colors termed red by livestock breeders. Medium brown is more rare in the
Pygmy breed than dark brown. The light brown of the Toggenburg is not present
in the Pygmy breed, is very visually distinct from the two browns in the Pygmy
breed, and probably represents a third type of brown in goats.
MATERIALS AND METHODS
Data from a herd of Pygmy goats in which both dark-brown and medium-brown
goats occurred were available for study. Dark-brown goats were used for several
matings, and the resulting figures were tested by statistical analysis for goodness of
fit to the hypothesis that dark brown is dominant to black. Medium-brown goats
were also used for several matings, and the resulting data were tested for goodness
of fit to the hypothesis that medium brown is recessive to black.
RESULTS
The results of various crosses are presented in table I. Black goats mated to
black goats produced over 100 kids, none of which were dark brown. The mating
of black goats to dark-brown goats produced 23 black and 17 dark-brown kids.
These results agree with the hypothesis that dark brown is due to a gene (Bd)
that is dominant to black (wild type, B+), and that all dark-brown parents are
heterozygous (B dB+): chi2 = 0.9, 1 df, P > 0.05. The mating of dark-brown goats
to dark-brown goats produced no black and seven dark-brown kids. These results
agree with the hypothesis that dark brown is due to a gene (Bd) that is dominant
to black (B+), and that all parental dark-brown goats are heterozygous (B!B!),
binomial test, P = 0.13.
Medium-brown goats mated to black goats produced 62 black and four medium-
brown kids. These results do not support the hypothesis that medium brown is
due to a gene (Bb) that is dominant to black (B+): chi2 = 51, 1 df, P < 0.01.
If medium brown is recessive to black, the black goats heterozygous for the gene
and those not heterozygous for the gene cannot be adequately separated into two
classes even though they represent two different genotypes. Medium-brown goats
mated to black goats which had one medium-brown parent (these being obligate
heterozygotes under the hypothesis that medium brown is recessive) produced 42
black and 26 medium-brown kids. These results agree with the hypothesis that
medium brown (Bb) is recessive to black (wild type B+), and that the black goats
with a medium-brown parent are heterozygous (B6B+), while medium-brown goats
are homozygous (BbB): chi2 = 3.76, 1 df, P > 0.05. Medium-brown goats mated to
medium-brown goats produced 28 medium-brown kids, and no other colors, which
is consistent with its being a recessive gene.
The only occasion on which a dark-brown goat with a medium-brown parent
was mated to a medium-brown goat the kids were one dark brown and one medium
brown.
DISCUSSION
The homologies and interactions of the various browns in the literature are currently
uncertain, although some proposals are now possible. The two different types
of brown in the Pygmy goat, described in this report, have distinct patterns of
inheritance. Dark brown is dominant to black, and medium brown is recessive to
black. Pygmy goat owners rarely cross the two distinct types of brown, and therefore
a complete test of allelism was not possible from the data. The single mating of
interest for a test of allelism was of a dark-brown animal, carrying medium brown,
to a medium-brown goat. The resulting kids, one dark and one medium-brown, are
consistent with the two being allelic, but the numbers are too few for this to be a
complete test.
The alleles for dark brown and medium brown, plus a wild type allele, can be
provisionally assigned to the Brown locus, since considerations of homology suggest
that they belong there. The symbol Bd is proposed for the dominant dark brown
alleles to be in keeping with recommendations of COGNOSAG (1995). This is
probably the same as the rossa (Br) color noted in Lauvergne and Howell (1978).
The symbol B6 is proposed for the recessive medium brown allele (named brown),
since this is the allele that is most likely homologous with recessive brown in other
species.
The light-brown coat color that is typical of the Toggenburg breed has been
assigned to the Brown locus by Adalsteinsson et al (1994), with the symbol BB!.
The symbol should be changed to Bl to be in keeping with past recommendations
of COGNOSAG (Millar and Lauvergne, 1990), as well as current COGNOSAG
(1995) recommendations. The light brown allele is dominant to wild type. The light
brown discussed in Lauvergne and Howell (1978) could be homologous with either
the light brown of Adalsteinsson et al (1994), or the medium brown of this report.
The absence of segregation data in Lauvergne and Howell (1978) make it difficult
to assign their light brown with certainty.
The order of dominance within the Brown locus is probably B! ? Bd> B+ > Bb.
REFERENCES
Adalsteinsson S, Sponenberg DP, Alexieva S, Russell AJF (1994) Inheritance of goat coat
colors. J Hered 85, 267-272
Asdell SA, Buchanan Smith AD (1928) Inheritance of color, beard, tassels, and horns in
the goat. J Hered 19, 425-430
COGNOSAG (1995) Revised guidelines for gene nomenclature in ruminants (1993) Genet
Sel Evol 27, 89-93
Eidregevic EV (1941) A contribution to the problem of morphogenesis and evolution
of pigmentation in the goat. 1’r Buryat-Mong Zoovet Inst (Ulan-Ude) 2, 173-187 (in
Russian); Anim Breed Abstr 14, 237
Hards ER (1950) The inheritance of coat characteristics in the goats of the British Isles.
British Goat Society’s Year Book 67-69
Lauvergne JJ, Howell WE (1978) Un premier inventaire g6n6tique de la chèvre Corse.
Ethnozootechnie 22, 86-88
Millar P, Lauvergne JJ (1990) Loci for coat colour of goats. In: Loci for Coat Colour of
SheeP and Goats 1989 (JJ Lauvergne, ed), COGNOSAG, Clamart, France, 59-66


Dominant and recessive brown in goats

Crossref

NoteDominant and recessive brown in goatsDP Sponenberg1 C LaMarsh21 Virginia-Maryland Regional College of Veterinary Medicine,Virginia Tech, Blacksburg, VA 24061;2 Blue Berry Sunrise Farm Pygmy Goats, 14453 S Macksburg Rd,Molalla, OR 97038, USA(Received 2 May 1995; accepted 18 October 1995)Summary - Pygmy goats in the USA occur in a variety of colors including black, roan(called agouti by breeders), and badgerface. In a minority of animals the black areas arereplaced by dark brown or medium brown. The colors of kids from matings among black,dark-brown, and medium-brown goats were observed. The results are consistent with threealleles at the Brown locus: dark brown (Bd) dominant to wild type (B+) which is dominantto medium brown Bb).goat / genetics / coat color / brown / Pygmy goatRésumé - Bruns dominant et récessif chez la chèvre. Les chèvres Pygmy des ÉtatsUnis présentent une variété de couleurs comprenant le noir, le rouan (appelé agouti parles éleveurs), et « face de blaireau» («badger face»). Chez quelques animaux les zonesnoires sont remplacées par du brun foncé ou du brun moyen. On a observé des chevreauxissus de croisements entre des parents noirs, brun foncé ou brun moyen. Les résultats sonten accord avec l’existence de trois allèles au locus Brun: le brun foncé (Nd) dominant surle type sauvage (B+) lui-même dominant sur le brun moyen (Bb).chèvre / génétique / couleur de robe / brun / chèvre PygmyINTRODUCTIONInheritance of coat color in goats has received less attention than has that of sheep,primarily due to the economic importance of white sheep’s wool and lack of asimilar importance for color in most goats. Recent work (Adalsteinsson et al, 1994)has documented the similarity of the genetic control of many goat colors to sheepcolors.The relationship of brown to black eumelanin in goats is one aspect of colorgenetics that has been studied repeatedly with conflicting results. Early worksinclude those of Asdell and Buchanan Smith (1928) and Eidregevic (1941), whoconcluded that brown was dominant to black. This was further substantiated byHards (1950). Lauvergne and Howell (1978) postulate that both brown and lightbrown are recessive to black, but segregation data were not available for analysis.Adalsteinsson et al (1994) conclude that light brown, typical of the Toggenburgbreed, is dominant to black. The general conclusion one can draw from past workis that brown is dominant to black, and that this brown is the light brown ofthe Toggenburg breed. Other types of brown have been less well documented bysegregation data.Two types of brown are present in the Pygmy goat breed in the USA. Thatthese are eumelanic is substantiated by the fact that each of these browns is seenin conjunction with the badgerface pattern (termed caramel in this breed) in whichthe browns replace black in the typical pattern. These two types of brown aredistinct, and are easily recognized by breeders. One is a dark brown, and is oftencalled cocoa brown by breeders. This is a very dark brown. The other is a mediumbrown which is much lighter and brighter than the dark brown, and is termed redby breeders even though it is an eumelanic phenomenon, and not pheomelanic asare most colors termed red by livestock breeders. Medium brown is more rare in thePygmy breed than dark brown. The light brown of the Toggenburg is not presentin the Pygmy breed, is very visually distinct from the two browns in the Pygmybreed, and probably represents a third type of brown in goats.MATERIALS AND METHODSData from a herd of Pygmy goats in which both dark-brown and medium-browngoats occurred were available for study. Dark-brown goats were used for severalmatings, and the resulting figures were tested by statistical analysis for goodness offit to the hypothesis that dark brown is dominant to black. Medium-brown goatswere also used for several matings, and the resulting data were tested for goodnessof fit to the hypothesis that medium brown is recessive to black.RESULTSThe results of various crosses are presented in table I. Black goats mated toblack goats produced over 100 kids, none of which were dark brown. The matingof black goats to dark-brown goats produced 23 black and 17 dark-brown kids.These results agree with the hypothesis that dark brown is due to a gene (Bd)that is dominant to black (wild type, B+), and that all dark-brown parents areheterozygous (B dB+): chi2 = 0.9, 1 df, P > 0.05. The mating of dark-brown goatsto dark-brown goats produced no black and seven dark-brown kids. These resultsagree with the hypothesis that dark brown is due to a gene (Bd) that is dominantto black (B+), and that all parental dark-brown goats are heterozygous (B!B!),binomial test, P = 0.13.Medium-brown goats mated to black goats produced 62 black and four medium-brown kids. These results do not support the hypothesis that medium brown isdue to a gene (Bb) that is dominant to black (B+): chi2 = 51, 1 df, P < 0.01.If medium brown is recessive to black, the black goats heterozygous for the geneand those not heterozygous for the gene cannot be adequately separated into twoclasses even though they represent two different genotypes. Medium-brown goatsmated to black goats which had one medium-brown parent (these being obligateheterozygotes under the hypothesis that medium brown is recessive) produced 42black and 26 medium-brown kids. These results agree with the hypothesis thatmedium brown (Bb) is recessive to black (wild type B+), and that the black goatswith a medium-brown parent are heterozygous (B6B+), while medium-brown goatsare homozygous (BbB): chi2 = 3.76, 1 df, P > 0.05. Medium-brown goats mated tomedium-brown goats produced 28 medium-brown kids, and no other colors, whichis consistent with its being a recessive gene.The only occasion on which a dark-brown goat with a medium-brown parentwas mated to a medium-brown goat the kids were one dark brown and one mediumbrown.DISCUSSIONThe homologies and interactions of the various browns in the literature are currentlyuncertain, although some proposals are now possible. The two different typesof brown in the Pygmy goat, described in this report, have distinct patterns ofinheritance. Dark brown is dominant to black, and medium brown is recessive toblack. Pygmy goat owners rarely cross the two distinct types of brown, and thereforea complete test of allelism was not possible from the data. The single mating ofinterest for a test of allelism was of a dark-brown animal, carrying medium brown,to a medium-brown goat. The resulting kids, one dark and one medium-brown, areconsistent with the two being allelic, but the numbers are too few for this to be acomplete test.The alleles for dark brown and medium brown, plus a wild type allele, can beprovisionally assigned to the Brown locus, since considerations of homology suggestthat they belong there. The symbol Bd is proposed for the dominant dark brownalleles to be in keeping with recommendations of COGNOSAG (1995). This isprobably the same as the rossa (Br) color noted in Lauvergne and Howell (1978).The symbol B6 is proposed for the recessive medium brown allele (named brown),since this is the allele that is most likely homologous with recessive brown in otherspecies.The light-brown coat color that is typical of the Toggenburg breed has beenassigned to the Brown locus by Adalsteinsson et al (1994), with the symbol BB!.The symbol should be changed to Bl to be in keeping with past recommendationsof COGNOSAG (Millar and Lauvergne, 1990), as well as current COGNOSAG(1995) recommendations. The light brown allele is dominant to wild type. The lightbrown discussed in Lauvergne and Howell (1978) could be homologous with eitherthe light brown of Adalsteinsson et al (1994), or the medium brown of this report.The absence of segregation data in Lauvergne and Howell (1978) make it difficultto assign their light brown with certainty.The order of dominance within the Brown locus is probably B! ? Bd> B+ > Bb.REFERENCESAdalsteinsson S, Sponenberg DP, Alexieva S, Russell AJF (1994) Inheritance of goat coatcolors. J Hered 85, 267-272Asdell SA, Buchanan Smith AD (1928) Inheritance of color, beard, tassels, and horns inthe goat. J Hered 19, 425-430COGNOSAG (1995) Revised guidelines for gene nomenclature in ruminants (1993) GenetSel Evol 27, 89-93Eidregevic EV (1941) A contribution to the problem of morphogenesis and evolutionof pigmentation in the goat. 1’r Buryat-Mong Zoovet Inst (Ulan-Ude) 2, 173-187 (inRussian); Anim Breed Abstr 14, 237Hards ER (1950) The inheritance of coat characteristics in the goats of the British Isles.British Goat Society’s Year Book 67-69Lauvergne JJ, Howell WE (1978) Un premier inventaire g6n6tique de la chèvre Corse.Ethnozootechnie 22, 86-88Millar P, Lauvergne JJ (1990) Loci for coat colour of goats. In: Loci for Coat Colour ofSheeP and Goats 1989 (JJ Lauvergne, ed), COGNOSAG, Clamart, France, 59-66

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Dominant and recessive brown in goats

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