Inheritance of Coat Color of Kejobong Goat in Purbalingga Regency, Central Java, Indonesia

The objective of this research was to examine the inheritance of coat color pattern of Kejobonggoat. The material used was goat family with clear lineage, in which the number of samples were 130Kejobong family, consisted of 201 kids, 130 does and 51 bucks. Coat color of black, black white, blackbrown, brown, white brown and white, were observed. The coat color types were classified andgenetically grouped according to the pigmentation types and color patterns. Probability compilationgene of coat color of Kejobong goat were B-C-S-ii (black), -- cc -- -- (white), BBC-ssii (black white),BbC-ssii (black brown), bbC-ssii (white brown) and bbC-S-ii (brown). Inheritance of coat colorobserved and fenotipe ratio expected were used to calculate Chi-square. Results of study showed that theinheritance of coat color pattern of Kejobong goat were not in Hardy-Weinberg equilibrium withexeption of mating between black and black brown and mating between brown black and white brownshowing similarity in observations and expectations.


INTRODUCTION
The goat is productive animal, easy to be handled and adapted to a various tropical environmental conditions, that is insufficient environment and management. Therefore, the selection may occur and resulted in a new breed like Kejobong goat.
Kejobong goat is a new breed resulted from crossbreeding between Etawa and Kacang breeds, and concentrated in Purbalingga Regency, Central Java, especially in Kejobong District (Kurnianto et al., 2013). According to Dinas Peternakan dan Perikanan Kabupaten Purbalingga (2013), the number of Kejobong goats in 2013 was about 43.708 heads spreading in 18 subdistrict. The most population of Kejobong goat was in Kejobong subdistrict (20.906 heads), then Pengadegan subdistrict (10.476 heads).
Coat color expression is controlled by a gene may be use as breed indicator (Inounu et al., 2009), and therefore could be used as a selection criteria of small ruminant in the tropical environment (Peters et al., 1982;Adedeji et al., 2011;Adedeji, 2012). Coat color is characteristic trait that easy to be identified, therefore it was used as phenotypic model in studying of gene expression and correlation among traits. Inheritance of coat color is influence by of polygene in each breed, although few of gene express color pattern in each individu (Trifena et al., 2011). Pigmentation traits expressed in animals are visual characteristics to distinguish among breeds and strains within breed (Liu et al., 2009). The combination of colors from two different breeds will result a mixed of colors to produce color variations in the offspring (Beatriz et al., 2007).
Inheritance of color in Angora goats deviates from mechanisms previously reported in other breeds and types of goats as reported by Sponenberg et al. (1998). Here, it is important to know the inheritance of coat color in Kejobong goats to decide a mating pattern in order to obtain offspring with a certain color. Inheritance of coat color in Kejobong goats has not been studied yet. Based this reason, a study to examine the inheritance of coat color pattern of Kejobong goat was conducted.

MATERIALS AND METHODS
The materials used in this research were goats family found in Purbalingga regency, spreading in four subdistrict such as Kejobong, Pengadegan, Bukateja and Kaligondang. Purposive sampling was applied to determine location based on the population density of the Kejobong goat in Purbalingga regency. Goat families with clear lineage were used as the sample. The number of samples were 130 Kejobong goats family consisted of 201 kids, 130 does and 51 bucks. Five groups of coat color were recorded, those were black coat color, black white, black brown, brown, white brown and white. Some of coat color patterns in Kejobong goat are presented in Figure 1.

Statistical Analysis
The coat color of parent and offspring were classified and genetically grouped according to the pigmentation types and color patterns. BBC-ssii (black white), BbC-ssii (black brown), bbC-ssii (white brown) dan bbC-S-ii (brown). On the basis of coat color, all possibilities of mating were constructed, then expected phenotypic ratio was obtained. Observation result on color pedigree and expected phenotypic ratio was used in Chi-square analysis (Noor, 2000;Sudjana, 2005;Yakubu et al., 2010). The formula of Chisquare is: Where: In this study, there was some zero number in the expectation. In this case, all elements both of observation and expectation were added by 1 value in order to Chi-square could be perfomed.

RESULTS AND DISCUSSION
The possibility of genotype of coat color in Kejobong goat is: bbC-ssii (bbCcssii / bbCCssii) 6. Brown bbC-S-ii (bbCCSSii / bbCcSSii / bbCCSsii / bbCcSsii) Table 1 presents mating between black and black color producing the offspring with black color (33.33%), black white (33.33%) and black brown (33.33%). Expected ratio was obtained from all possible matings between those two parents. The largest of expected number of color (70.54%) was black (B-CCS-ii), whereas the smallest one (1.49%) was white brown. The observation of the expected values showed highly significant difference (P<0.01). It means that the differences between observations and expectations were not in Hardy-Weinberg equilibrium. Based on the expectations, mating goat between black and black produced most of the black color in their offsprings. The fewest color in the expectation was white brown. It was observed the black, black white and black brown in the offprings, but no found the brown, white brown and white although it may occure in the expectation.
The occurrences of black color in the offspring (B-CCS-ii) was due to the presence of B gene either homozygous or heterozygous dominant in both of the parents. This is in agreement with the statement of Sponenberg et al. (1998) that the expression of eumelanin as either black or brown was controlled by the brown gene. Furthermore, it stated by Adalsteinsson (1991) that brown loci produce black or brown with the presence of eumelanin pigment. Noor (2000) stated that the genes in the B locus will determine whether melanin be changed into black or brown color. The B dominant gene would produce black color.
Appearance of black white color (BBC-ssii) and black brown (BBC-ssii) were due to the S gene in a homozygous recessive (ss) causing spot colors. According to Adalsteinsson (1991), spotting locus indicated the presence or absence of the recessive white markings. According to Noor (2000) and Axenovich et al. (2004), irregular spotting patterns (piebald) was recessive Inheritance of Coat Color in Kejobong Goat (T. Permatasari et al.) 139 (ss) inherited. The dominant allele (S) will generate a smooth color pattern. Table 2 shows that black goat mated to black white resulted in black white offspring (46.67%), followed by black (25%), black brown (20%) and white brown (8.33%). Black offspring was the largest number in expectations (57.32%), while the smallest one was brown (1.22%).
The results of the Chi-square test from the mating of black color to black white showed highly significant differences (P<0.01). It means that mating between those two colors resulted in color in disequilibrium of Hardy-Weinberg Law. This was possible due to the uncontrolled selection for black color conducted by farmers at hundreds year ago. Migration of goat from-and to other area may also creas stated by Kurnianto (2009) that the gene and genotypic frequencies in a population may not change from generation to generation long as there is no mutation, migration (genetic flow), genetic drift and selection (Hardy-Weinberg Law). According to Lasley (1978), the frequency of an allele possibility may differ if there is a selection. Selection can increase the frequency of some genes and decreased the frequency of other genes.
The highly significant differences (P<0.01) was found in offspring coat color from mating between parent in black and white brown (Table  3). It means that the difference between observations and expectations were not in Hardy-Weinberg equilibrium. Meanwhile, there was no significantly difference in offspring coat color resulted from mating of black to black brown (Table 4), in which this result was in Hardy-Weinberg equilibrium. The black and black brown offspring were the most found from the mating between black (B-CCS-ii) and black brown (BBC-ssii).
The mating of parents between black white and black white (Table 5) showed highly significant differences (P<0.01) indicating the mating between those colors were not in the Hardy-Weinberg equilibrium. The black white or white black (BBC-ssii) will predominantly generate black white offspring, followed by 3 other colors, those were Black (B-CCS-ii), black brown (BbC-ssii) and white brown (bbC-ssii).   color occured due to the presence of gene c and gene I. According to Noor (2000), the white color is caused by the inhibitor of I dominant gene.
Recessive genotype (ii) allow the appearance of color which is controlled by another gene. The I dominant gene depress the development of melanin with the concequence in producing white coat color. In addition, the white color is caused by a recessive cc gene homozygote, while the other colors are caused by a dominant C gene. The recessive white gene is different from albino, because the albino is a pigmentation in the eye. The highly significant differences (P<0.01) was found from mating of black white to brown black (Table 6), indicating the mating of these two colors were not in the Hardy-Weinberg equilibrium. This mating resulted in most similarity both in observation and expectation for black white (BBC-ssii).
Mating of white brown color to black white (Table 7) showed highly significant differences (P<0.01), indicating the observation and expectation were not in Hardy-Weinberg equilibrium. This resulted was possible due to the uncontrolled selection and migration. In fact, variation of Kejobong coat color are still found as reported by Kurnianto et al. (2012). Table 8 presents the possibility of offspring genotypes when whe brown and white parents were mated each other. The result showed significant difference (P<0.05), indicating disequilibrium of Hardy-Weinberg Law. Mating between these two colors just resulted in white brown. The existence white brown color was due to the b gene and s gene, while the white color appeared due to the c gene and the I gene (inhibitor gene). This is in agreement to Noor (2000) that the albino gene in mammals is an excellent exampcessive epistasis gene. The C dominant gene controls the production of melanin, while recessive homymes producing melanin, so that the appeared colors are white. According to Tang et al. (2008), pigmentation in mammalian is controlled by eumelanin and pheomelanin in melanocytes. Chen et al. (2012) stated that tyrosinase is the regulatory enzyme of melanogenesis and plays a major role in mammal coat color. Melanogenesis takes place in various celltypes. Melanin is present as the black-brown eumelanin and the yellow-red pheomelanin, and the ratio and amount of the two pigments determine the color of the skin, eyes, and hair. Table 9 show mating of white brown and white brown highly significant differences   Lasley (1978) the migration is a factor that can lead to changes in gene frequency expressing coat color The highly significant differences (P<0.01) was found in offspring coat color resulted from mating of brown black and brown black (Table  10). This result indicated that difference between observations and expectations were not in Hardy-Weinberg equilibrium. Brown black color in offspring was due to gene B, gene b and s. According to Adalsteinsson (1991), the locus brown may produce black or brown pigment in the presence of eumelanin. According to Noor (2000), the pattern of irregular white patches (piebald) is inherited as recessive (ss).
The offspring coat color resulted from mating between two parents of brown black color and white brown (Table 11) were not significantly different (P>0.01). It means that this results were in Hardy-Weinberg equilibrium.

CONCLUSION
The inheritance of coat color of Kejobong goat was not in Hardy-Weinberg equilibrium with exeption of mating between black and black brown and mating between brown black and white brown showing similarity in observations and expectations.