BACKGROUND
significant development and refinement of analytical tools has resulted in identification of causal genes underlying qtls  for various economic traits.
is the detection of sequence variations of causal genes affecting the traits of interest are now possible in humans, animals and plants  <cit> .
several studies in cattle  <cit>  identified a qtl for milk production traits especially the milk fat percentage on chromosome  <dig>  near the centromeric region.
a comparative positional candidate gene approach led to identification of the candidate gene coding acylcoa: diacylglycerol – acyltransferase  <dig> .
dgat <dig> is considered to be the key enzyme in controlling the synthesis rate of triglycerides in adipocytes.
smith et al.
<cit>  demonstrated absence of lactation in knockout mice lacking both copies of dgat <dig>  grisart et al.
<cit> , winter et al.
<cit>  and weller et al.
<cit>  identified a polymorphism in exon  <dig> of the dgat <dig> gene in bos taurus, aa → gc exchange resulting in a non conservative substitution of amino acid  <dig> lysine  → alanine .
this polymorphism has been associated with increased fat yield, fat and protein percent as well as decrease in milk and protein.
another segregating qtl for milk production trait on bta  <dig> was found by many workers in various populations of bos taurus  <cit> .
the qtl centered around microsatellite bm <dig>  olsen et al.
<cit>  used physical mapping and combined linkage and linkage disequilibrium mapping to fine map qtl region between abcg <dig> and lap <dig>  several genes like pkd <dig>  <cit> , spp <dig>  gene  <cit>  and abcg <dig>  <cit>  have been proposed as candidate genes in the qtl region.
cohen-zinder et al.
<cit>  analysed the sequence variation of these genes and demonstrated that abcg <dig>  allele  to be the only polymorphism which corresponded to the segregation status of the heterozygous and homozygous sires for the qtl based on the allele substitution effect.
these two qtns  dgat1k and abcg2y are proposed non conservative mutations in bos taurus associated with increased fat yield, fat and protein percent as well as decrease in milk yield.
a study was carried out to adjudge the status of these mutations in bos indicus and bubalus bubalis.
RESULTS
the sequence obtained for segment of dgat <dig> in cattle  and buffalo ; have been submitted to ncbi database.
the sequence analysis of dgat <dig> region in six breeds of cattle  and  <dig> breeds of buffalo  revealed fixed dgat1k allele .
the sequence of desired region of control individuals revealed heterozygous condition for reported mutation in  <dig> animals.
no variation was observed in all the  <dig> breeds of cattle and buffalo undertaken in this study.
kaupe et al,  <cit>  had reported fixed dgat1k allele in nellore cattle.
lacorta et al  <cit>  also reported absence of a allele in nellore and guzerat cattle and very low frequency  in gyr and redsindhi cattle of brazil.
high frequency of dgat1a has recently been reported in uruguayan creole cattle  <cit>  and holstein and its crosses  <cit> .
this polymorphism has been associated with increased fat yield, fat and protein percent as well as decrease in milk and protein production.
the sequence obtained for abcg <dig>  have been submitted to ncbi database.
the analysis of sequence of abcg <dig> region in indian breeds of cattle  and buffalo  revealed fixed abcg2y allele .
only one animal of control group was heterozygous for abcg <dig> allele.
cohen-zinder et al,  <cit>  reported increase in frequency of abcg2y allele with selction for higher milk fat and protein percentage in the israeli holstein population.
CONCLUSIONS
this study provides an indirect evidence that all the indian cattle and buffalo breeds have fixed alleles with respect to dgat <dig> and abcg <dig> genes reported to be responsible for higher milk fat yield, higher fat and protein percent.
there is considerable genetic variation in milk production in india which can be exploited to increase the milk yield without having an adverse effect on fat and protein percent.

 significant development and refinement of analytical tools has resulted in identification of causal genes underlying qtls for various economic traits. is the detection of sequence variations of causal genes affecting the traits of interest are now possible in humans, animals and plants. several studies in cattle identified a qtl for milk production traits especially the milk fat percentage on chromosome near the centromeric region. a comparative positional candidate gene approach led to identification of the candidate gene coding acylcoa: diacylglycerol – acyltransferase. dgat is considered to be the key enzyme in controlling the synthesis rate of triglycerides in adipocytes. smith et al. demonstrated absence of lactation in knockout mice lacking both copies of dgat grisart et al., winter et al. and weller et al. identified a polymorphism in exon of the dgat gene in bos taurus, aa → gc exchange resulting in a non conservative substitution of amino acid lysine → alanine. this polymorphism has been associated with increased fat yield, fat and protein percent as well as decrease in milk and protein. another segregating qtl for milk production trait on bta was found by many workers in various populations of bos taurus. the qtl centered around microsatellite bm olsen et al. used physical mapping and combined linkage and linkage disequilibrium mapping to fine map qtl region between abcg and lap several genes like pkd, spp gene and abcg have been proposed as candidate genes in the qtl region. cohen-zinder et al. analysed the sequence variation of these genes and demonstrated that abcg allele to be the only polymorphism which corresponded to the segregation status of the heterozygous and homozygous sires for the qtl based on the allele substitution effect. these two qtns dgat1k and abcg2y are proposed non conservative mutations in bos taurus associated with increased fat yield, fat and protein percent as well as decrease in milk yield. a study was carried out to adjudge the status of these mutations in bos indicus and bubalus bubalis.  the sequence obtained for segment of dgat in cattle and buffalo; have been submitted to ncbi database. the sequence analysis of dgat region in six breeds of cattle and breeds of buffalo revealed fixed dgat1k allele. the sequence of desired region of control individuals revealed heterozygous condition for reported mutation in animals. no variation was observed in all the breeds of cattle and buffalo undertaken in this study. kaupe et al, had reported fixed dgat1k allele in nellore cattle. lacorta et al also reported absence of a allele in nellore and guzerat cattle and very low frequency in gyr and redsindhi cattle of brazil. high frequency of dgat1a has recently been reported in uruguayan creole cattle and holstein and its crosses. this polymorphism has been associated with increased fat yield, fat and protein percent as well as decrease in milk and protein production. the sequence obtained for abcg have been submitted to ncbi database. the analysis of sequence of abcg region in indian breeds of cattle and buffalo revealed fixed abcg2y allele. only one animal of control group was heterozygous for abcg allele. cohen-zinder et al, reported increase in frequency of abcg2y allele with selction for higher milk fat and protein percentage in the israeli holstein population.  this study provides an indirect evidence that all the indian cattle and buffalo breeds have fixed alleles with respect to dgat and abcg genes reported to be responsible for higher milk fat yield, higher fat and protein percent. there is considerable genetic variation in milk production in india which can be exploited to increase the milk yield without having an adverse effect on fat and protein percent. 
this study provides an indirect evidence that all the indian cattle and buffalo breeds have fixed alleles with respect to dgat and abcg genes reported to be responsible for higher milk fat yield, higher fat and protein percent. the identification of qtls on bta and bta and its subsequent fine mapping has led to identification of two non conservative mutations affecting milk production and composition. our objective was to estimate the frequency of k232a and y581s polymorphisms in diverse cattle and buffalo breeds of india having large variation in terms of milk production. indian cattle and riverine buffalo give a poor yield of milk but it has a high fat and protein percentage compared to taurine cattle. we screened the reported missense mutations in six cattle and five buffalo breeds. the dgat1k and abcg2y alleles were found to be fixed in indian cattle and buffalo breeds studied.
 indian cattle and riverine buffalo give a poor yield of milk but it has a high fat and protein percentage compared to taurine cattle. the identification of qtls on bta and bta and its subsequent fine mapping has led to identification of two non conservative mutations affecting milk production and composition. our objective was to estimate the frequency of k232a and y581s polymorphisms in diverse cattle and buffalo breeds of india having large variation in terms of milk production.  we screened the reported missense mutations in six cattle and five buffalo breeds. the dgat1k and abcg2y alleles were found to be fixed in indian cattle and buffalo breeds studied.  this study provides an indirect evidence that all the indian cattle and buffalo breeds have fixed alleles with respect to dgat and abcg genes reported to be responsible for higher milk fat yield, higher fat and protein percent. 