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1.
Several reports have demonstrated that bovine chromosome 26 (BTA26) harbours significant or suggestive quantitative trait loci (QTL) for milk production and composition traits in dairy cattle. Our previous study showed that a C/T substitution in the bovine TCF7L2 gene on BTA26 was significantly linked to QTL for protein yield (PY) in a Canadian dairy cattle population. Actually, this polymorphism was one of the markers derived from a genome‐wide screening of QTL for milk PY using an amplified fragment length polymorphism technique combined with a DNA pooling strategy. In the present study, 990 Holstein bulls with complete genotype and phenotype data from 14 sire families were analysed to confirm, if the QTL effects exist in other populations. Statistical analysis revealed that this marker was significantly associated with PY, protein percentage, milk yield and fat yield (FY) (p < 0.001) in the US Holstein population. These results indicate that this QTL region has a pleiotrophic effect on different milk traits and is portable in different populations.  相似文献   

2.
Decreased calving performance not only directly impacts the economic efficiency of dairy cattle farming but also influences public concern for animal welfare. Previous studies have revealed a QTL on Bos taurus autosome (BTA) 18 that has a large effect on calving traits in Holstein cattle. In this study, fine mapping of this QTL was performed using imputed high‐density SNP chip (HD) genotypes followed by imputed next‐generation sequencing (NGS) variants. BTA18 was scanned for seven direct calving traits in 6113 bulls with imputed HD genotypes. SNP rs136283363 (BTA18: 57 548 213) was consistently the most significantly associated SNP across all seven traits [e.g. p‐value = 2.04 × 10?59 for birth index (BI)]. To finely map the QTL region and to explore pleiotropic effects, we studied NGS variants within the targeted region (BTA18: 57 321 450–57 625 355) for associations with direct calving traits and with three conformation traits. Significant variants were prioritized, and their biological relevance to the traits was interpreted. Considering their functional relationships with direct calving traits, SIGLEC12, CD33 and CEACAM18 were proposed as candidate genes. In addition, pleiotropic effects of this QTL region on direct calving traits and conformation traits were observed. However, the extent of linkage disequilibrium combined with the lack of complete annotation and potential errors in the Bos taurus genome assembly hampered our efforts to pinpoint the causal mutation.  相似文献   

3.
The primary aim of this study was to investigate the quantitative trait loci (QTL) on BTA6 that affect negatively correlated milk traits, using bivariate covariance component analysis of milk yield and fat (or protein) content, protein yield and fat content, and fat yield and protein content. A set of five different genetic models was adapted to differentiate trait‐specific QTL in close linkage from pleiotropy. Using a grand‐daughter design consisting of five half‐sib families from the German Holstein population and 298 sons genotyped for 16 microsatellite markers on BTA6, we found significant trait‐specific QTL for fat content and protein yield, 24 cM apart. Markers BM1329 and FBN12 bracketed the QTL for fat content, and the region between TGLA37 and FBN13 most likely harbours a QTL for protein yield. The analysis based on the close linkage model fully confirmed this result. Despite the pure QTL findings confirming results from the literature, distinguishing pleiotropic and closely linked QTL for competitive traits is a new aspect. Our multivariate analysis results did not suggest a pleiotropic QTL for the investigated negatively correlated traits. The QTL‐based trait correlations were discussed as an important aspect of modelling that needs to be considered in the future.  相似文献   

4.
A primary genomic screen for quantitative trait loci (QTL) affecting carcass and growth traits was performed by genotyping 238 microsatellite markers on 185 out of 300 total progeny from a Bos indicus x Bos taurus sire mated to Bos taurus cows. The following traits were analyzed for QTL effects: birth weight (BWT), weaning weight (WW), yearling weight (YW), hot carcass weight (HCW), dressing percentage (DP), fat thickness (FT), marbling score (MAR), longissimus muscle area (LMA), rib bone (RibB), rib fat (RibF), and rib muscle (RibM), and the predicted whole carcass traits, retail product yield (RPYD), fat trim yield (FATYD), bone yield (BOYD), retail product weight (RPWT), fat weight (FATWT), and bone weight (BOWT). Data were analyzed by generating an F-statistic profile computed at 1-cM intervals for each chromosome by the regression of phenotype on the conditional probability of receiving the Brahman allele from the sire. There was compelling evidence for a QTL allele of Brahman origin affecting an increase in RibB and a decrease in DP on chromosome 5 (BTA5). Putative QTL at or just below the threshold for genome-wide significance were as follows: an increase in RPYD and component traits on BTA2 and BTA13, an increase in LMA on BTA14, and an increase in BWT on BTA1. Results provided represent a portion of our efforts to identify and characterize QTL affecting carcass and growth traits.  相似文献   

5.
We used a half-sib family of purebred Japanese Black (Wagyu) cattle to locate economically important quantitative trait loci. The family was composed of 348 fattened steers, 236 of which were genotyped for 342 microsatellite markers spanning 2,664 cM of 29 bovine autosomes. The genome scan revealed evidence of 15 significant QTL (<5% chromosome-wise level) affecting growth and carcass traits. Of the 15 QTL, six QTL were significant at the 5% experiment-wise level and were located in bovine chromosomes (BTA) 4, 5, and 14. We analyzed these three chromosomes in more detail in the 348 steers, with an average marker interval of 1.2 cM. The second scan revealed that the same haplotype of the BTA 4 region (52 to 67 cM) positively affected LM area and marbling. We confirmed the QTL for carcass yield estimate on BTA 5 in the region of 45 to 54 cM. Five growth-related QTL located on BTA 14, including slaughter and carcass weights, were positively affected by the same region of the haplotype of BTA 14 (29-51 cM). These data should provide a useful reference for further marker-assisted selection in the family and positional cloning research. The research indicates that progeny design with moderate genotyping efforts is a powerful method for detecting QTL in a purebred half-sib family.  相似文献   

6.
The effects of the bovine myostatin gene on chromosome 2 on birth and carcass traits have been previously assessed. The objective of this study was to identify additional quantitative trait loci (QTL) for economically important traits in two families segregating an inactive copy of myostatin. Two half-sib families were developed from Belgian Blue x MARC III (n = 246) and Piedmontese x Angus (n = 209) sires. Traits analyzed were birth (kg) and yearling weight (kg); hot carcass weight (kg); fat depth (cm); marbling score; longissimus muscle area (cm2); estimated kidney, pelvic, and heart fat (%); USDA yield grade; retail product yield (%); fat yield (%); and wholesale rib-fat yield (%). Meat tenderness was measured as Warner-Bratzler shear force at 3 and 14 d postmortem. The effect of myostatin on these traits was removed by using phase information obtained from the previous study with six microsatellite markers flanking the locus. Selective genotyping was done on 92 animals from both families to identify genomic regions potentially associated with retail product yield and fat depth, using a total of 150 informative markers in each family. Regions in which selective genotyping indicated the presence of QTL were evaluated further by genotyping the entire population and additional markers. For the family with Belgian Blue inheritance (n = 246), a significant QTL for birth and yearling weight was identified on chromosome 6. Suggestive QTL were identified for longissimus muscle area and hot carcass weight on chromosome 6 and for marbling on chromosomes 17 and 27. For the family with Piedmontese inheritance (n = 209), suggestive QTL on chromosome 5 were identified for fat depth, retail product yield, and USDA yield grade and on chromosome 29 for Warner-Bratzler shear force at 3 and 14 d postmortem. Interactions suggesting the presence of QTL were observed between myostatin and chromosome 5 for Warner-Bratzler shear force at 14 d postmortem and between myostatin and chromosome 14 for fat depth. Thus, in families segregating an inactive copy of myostatin in cattle, other loci influencing quantitative traits can be detected. These results are the initial effort to identify and characterize QTL affecting carcass and growth traits in families segregating myostatin.  相似文献   

7.
Charolais cattle are one of the most important breeds for meat production worldwide; in México, its selection is mainly made by live weight traits. One strategy for mapping important genomic regions that might influence productive traits is the identification of signatures of selection. This type of genomic features contains loci with extended linkage disequilibrium (LD) and homozygosity patterns that are commonly associated with sites of quantitative trait locus (QTL). Therefore, the objective of this study was to identify the signatures of selection in Charolais cattle genotyped with the GeneSeek Genomic Profiler Bovine HD panel consisting of 77 K single nucleotide polymorphisms (SNPs). A total 61,311 SNPs and 819 samples were used for the analysis. Identification of signatures of selection was carried out using the integrated haplotype score (iHS) methodology implemented in the rehh R package. The top ten SNPs with the highest piHS values were located on BTA 4, 5, 6 and 14. By identifying markers in LD with top ten SNPs, the candidate regions defined were mapped to 52.8–59.3 Mb on BTA 4; 67.5–69.3 on BTA 5; 39.5–41.0 Mb on BTA 6; and 26.4–29.6 Mb on BTA 14. The comparison of these candidate regions with the bovine QTLdb effectively confirmed the association (p < 0.05) with QTL related to growth traits and other important productive traits. The genomic regions identified in this study indicated selection for growth traits on the Charolais population via the conservation of haplotypes on various chromosomes. These genomic regions and their associated genes could serve as the basis for haplotype association studies and for the identification of causal genes related to growth traits.  相似文献   

8.
A genome-wide scan for QTL affecting economically important traits in beef production was performed using an F(2) resource family from a Japanese Black x Limousin cross, where 186 F(2) animals were measured for growth, carcass, and meat-quality traits. All family members were genotyped for 313 informative microsatellite markers that spanned 2,382 cM of bovine autosomes. The centromeric region of BTA2 contained significant QTL (i.e., exceeding the genome-wide 5% threshold) for 5 carcass grading traits [LM area, beef marbling standards (BMS) number, luster, quality grade, and firmness), 8 computer image analysis (CIA) traits [LM lean area, ratio of fat area (RFA) to LM area, LM area, RFA to musculus (M.) trapezius area, M. trapezius lean area, M. semispinalis lean area, RFA to M. semispinalis area, and RFA to M. semispinalis capitis area], and 5 meat quality traits (contents of CP, crude fat, moisture, C16:1, and C18:2 of LM). A significant QTL for withers height was detected at 80.3 cM on BTA5. We detected significant QTL for the C14:0 content in backfat and C14:0 and C14:1 content in intermuscular fat around the 62.3 to 71.0 cM region on BTA19 and for C14:0, C14:1, C18:1, and C16:0 content and ratio of total unsaturated fatty acid content to total SFA content in intramuscular fat at 2 different regions on BTA19 (41.1 cM for C14:1 and 62.3 cM for the other 4 traits). Overall, we identified 9 significant QTL regions controlling 27 traits with genome-wide significance of 5%; of these, 22 traits exceeded the 1% genome-wide threshold. Some of the QTL affecting meat quality traits detected in this study might be the same QTL as previously reported. The QTL we identified need to be validated in commercial Japanese Black cattle populations.  相似文献   

9.
Fatty acid composition is one of the important traits in beef. The aim of this study was to identify candidate genomic regions for fatty acid composition by genome‐wide association study with 50 K single nucleotide polymorphism (SNP) array in Japanese Black cattle. A total of 461 individuals and 40 657 SNPs were used in this study. We applied genome‐wide rapid association using mixed model and regression (GRAMMAR) and genomic control approaches to estimate the associations between genotypes and fatty acid composition. In addition, two SNPs in fatty acid synthase (FASN) (T1952A) and stearoyl‐CoA desaturase (SCD) (V293A) genes were also genotyped. Association analysis revealed that 30 significant SNPs for several fatty acids (C14:0, C14:1, C16:1 and C18:1) were located in the BTA19 FASN gene located within this region but the FASN mutation had no significant effect on any traits. We also detected one significant SNP for C18:1 on BTA23 and two SNPs for C16:0 on BTA25. The region around 17 Mb on BTA26 harbored two significant SNPs for C14:1 and SNP in SCD in this region showed the strongest association with C14:1. This study demonstrated novel candidate regions in BTA19, 23 and 25 for fatty acid composition.  相似文献   

10.
This study was conducted to detect quantitative trait loci (QTL) affecting growth and beef carcass fatness traits in an experimental population of Angus and Brahman crossbreds. The three-generation mapping population was generated with 602 progeny from 29 reciprocal backcross and three F2 full-sib families, and 417 genetic markers were used to produce a sex-averaged map of the 29 autosomes spanning 2,642.5 Kosambi cM. Alternative interval-mapping approaches were applied under line-cross (LC) and random infinite alleles (RA) models to detect QTL segregating between and within breeds. A total of 35 QTL (five with genomewide significant and 30 with suggestive evidence for linkage) were found on 19 chromosomes. One QTL affecting yearling weight was found with genomewide significant evidence for linkage in the interstitial region of bovine autosome (BTA) 1, and an additional 19 QTL were detected with suggestive evidence for linkage under the LC model. Many of these QTL had a dominant (complete or overdominant) mode of gene action, and only a few of the QTL were primarily additive, which reflects the fact that heterosis for growth is known to be appreciable in crosses among Brahman and British breeds. Four QTL affecting growth were detected with genomewide significant evidence for linkage under the RA model on BTA 2 and BTA 6 for birth weight, BTA 5 for yearling weight, and BTA 23 for hot carcass weight. An additional 11 QTL were detected with suggestive evidence for linkage under the RA model. None of the QTL (except for yearling weight on BTA 5) detected under the RA model were found by the LC analyses, suggesting the segregation of alternate alleles within one or both of the parental breeds. Our results reveal the utility of implementing both the LC and RA models to detect dominant QTL and also QTL with similar allele frequency distributions within parental breeds.  相似文献   

11.
前期研究通过荷斯坦公牛全基因组重测序鉴定到17个奶牛产奶性状候选功能基因,其中,肽基脯氨酸顺反异构酶基因(PIN1)参与甘油三酯代谢、甘油磷脂代谢以及mTOR信号通路,且位于产奶量和乳蛋白量性状QTL区间.为进一步系统分析PIN1基因是否对奶牛产奶性状具有遗传效应,本实验基于40头公牛的基因组DNA混池,采用PCR产物...  相似文献   

12.
A whole genome scan to map quantitative trait loci (QTL) for persistency of milk yield (PMY), persistency of fat yield (PFY), persistency of protein yield (PPY) and persistency of milk energy yield (PEY) was performed in a granddaughter design in the German Holstein dairy cattle population. The analysis included 16 paternal half‐sib families with a total of 872 bulls. The analysis was carried out for the first lactation and for the first three lactations combined using univariate weighted multimarker regression. Controlling the false discovery rate across traits and data sets at a level of 0.15 and treating the four persistency traits as different traits revealed 27 significant QTL. A total of 12 chromosomes showed significant QTL effects on a chromosomewise basis. The DGAT1 effect was highly significant for PPY and protein yield. A haplotype analysis using results of previous studies of the same design revealed a co‐segregation of various persistency QTL and QTL affecting health traits like dystocia and stillbirth and functional traits like non‐return rate 90 and somatic cell score.  相似文献   

13.
Feed intake and feed efficiency are economically important traits in beef cattle because feed is the greatest variable cost in production. Feed efficiency can be measured as feed conversion ratio (FCR, intake per unit gain) or residual feed intake (RFI, measured as DMI corrected for BW and growth rate, and sometimes a measure of body composition, usually carcass fatness, RFI(bf)). The goal of this study was to fine map QTL for these traits in beef cattle using 2,194 markers on 24 autosomes. The animals used were from 20 half-sib families originating from Angus, Charolais, and University of Alberta Hybrid bulls. A mixed model with random sire and fixed QTL effect nested within sire was used to test each location (cM) along the chromosomes. Threshold levels were determined at the chromosome and genome levels using 20,000 permutations. In total, 4 QTL exceeded the genome-wise threshold of P < 0.001, 3 exceeded at P < 0.01, 17 at P < 0.05, and 30 achieved significance at the chromosome-wise threshold level (at least P < 0.05). No QTL were detected on BTA 8, 16, and 27 above the 5% chromosome-wise significance threshold for any of the traits. Nineteen chromosomes contained RFI QTL significant at the chromosome-wise level. The RFI(bf) QTL results were generally similar to those of RFI, the positions being similar, but occasionally differing in the level of significance. Compared with RFI, fewer QTL were detected for both FCR and DMI, 12 and 4 QTL, respectively, at the genome-wise thresholds. Some chromosomes contained FCR QTL, but not RFI QTL, but all DMI QTL were on chromosomes where RFI QTL were detected. The most significant QTL for RFI was located on BTA 3 at 82 cM (P = 7.60 x 10(-5)), for FCR on BTA 24 at 59 cM (P = 0.0002), and for DMI on BTA 7 at 54 cM (P = 1.38 x 10(-5)). The RFI QTL that showed the most consistent results with previous RFI QTL mapping studies were on BTA 1, 7, 18, and 19. The identification of these QTL provides a starting point to identify genes affecting feed intake and efficiency for use in marker-assisted selection and management.  相似文献   

14.
Because the priority of AI industry is to identify subfertile bulls, a predictive model that allowed for the prediction of 91% bulls of low fertility was implemented based on seminological (motility) parameters and DNA status assessed both as DNA fragmentation index (DFI) and by TUNEL assay using sperm of 105 Holstein–Friesian bulls (four batches per bull) selected based on in vivo estimated relative conception rates (ERCR). Thereafter, sperm quality and male fertility traits of bulls were explored by GWAS using a high‐density (777K) Illumina chip. After data editing, 85 bulls and 591,988 SNPs were retained for GWAS. Of 12 SNPs with false discovery rate <0.2, four SNPs located on BTA28 and BTA18 were significantly associated (LD‐adjusted Bonferroni <0.05) with the non‐compensatory sperm parameters DFI and TUNEL. Other SNPs of interest for potential association with TUNEL were found on BTA3, in the same chromosome where associations with non‐compensatory in vivo bull fertility were already reported. Further suggestive SNPs for sperm membrane integrity were located on BTA28, the chromosome where QTL studies previously reported associations with sperm quality traits. Suggestive SNPs for ERCR were found on BTA18 in the vicinity of a site already associated with in vivo bull fertility. Additional SNPs associated with ERCR and sperm kinetic parameters were also identified. In contrast to other, but very few GWAS on fertility traits in bovine spermatozoa, which reported significant SNPs located on BTX, we have not identified SNPs of interest in this sexual chromosome.  相似文献   

15.
Recent publications indicate genetic variation in milk production traits on proximal BTA14, which cannot be explained solely with genetic variation in the DGAT1 gene. To elucidate these QTL effects, animals from a German Holstein granddaughter design (18 families, 1,291 sons) were genotyped for CYP11B1 (V30A) and DGAT1 (K232A) polymorphisms. Frequencies of alleles of maternal descent were estimated for CYP11B1(V) (0.776) and DGAT1(K) (0.549). Allele substitution effects (alpha/2) were first calculated for both alleles in separate models and then in a joint model. From the joint analysis, CYP11B1(V) effects on fat content (+0.04%) and protein content (+0.01%) were positive. Effects on milk yield (-82 kg), fat yield (-0.5 kg), and protein yield (-1.9 kg) were negative. Compared with the individual analysis, DGAT1(K) effects on fat content (+0.28%), protein content (+0.06%), and milk yield (-258 kg) were reduced; fat yield (+10.8 kg) was enhanced; and protein yield (-3.8 kg) was reduced. In the joint analysis, allele substitution effects of CYP11B1(V) and DGAT1(K) together explained more of the variation in milk production traits than DGAT1(K) alone. Further significant effects were found for CYP11B1(V) and DGAT1(K) among 6 reproduction traits and 14 conformational traits. These observations indicate a possible negative influence of DGAT1(K) on maternal nonreturn rate, and thus, on length of productive life.  相似文献   

16.
The objective of this study was to identify quantitative trait loci for economically important traits in two families segregating an inactive copy of the myostatin gene. Two half-sib families were developed from a Belgian Blue x MARC III (n = 246) and a Piedmontese x Angus (n = 209) sire. Traits analyzed were birth, weaning, and yearling weight (kg); preweaning average daily gain (kg/d); postweaning average daily gain (kg/d); hot carcass weight (kg); fat depth (cm); marbling score; longissimus muscle area (cm2); estimated kidney, pelvic, and heart fat (%); USDA yield grade; retail product yield (%); fat yield (%); and wholesale rib-fat yield (%). Meat tenderness was measured as Warner-Bratzler shear force at 3 and 14 d postmortem. The effect of the myostatin gene was removed using phase information from six microsatellite markers flanking the locus. Interactions of the myostatin gene with other loci throughout the genome were also evaluated: The objective was to use markers in each family, scanning the genome approximately every 25 to 30 centimorgans (cM) on 18 autosomal chromosomes, excluding 11 autosomal chromosomes previously analyzed. A total of 89 markers, informative in both families, were used to identify genomic regions potentially associated with each trait. In the family of Belgian Blue inheritance, a significant QTL (expected number of false-positives = 0.025) was identified for marbling score on chromosome 3. Suggestive QTL for the same family (expected number of false-positives = 0.5) were identified for retail product yield on chromosome 3, for hot carcass weight and postweaning average daily gain on chromosome 4, for fat depth and marbling score on chromosome 8, for 14-d Warner-Bratzler shear force on chromosome 9, and for marbling score on chromosome 10. Evidence suggesting the presence of an interaction for 3-d Warner-Bratzler shear force between the myostatin gene and a QTL on chromosome 4 was detected. In the family of Piedmontese and Angus inheritance, evidence indicates the presence of an interaction for fat depth between the myostatin gene and chromosome 8, in a similar position where the evidence suggests the presence of a QTL for fat depth in the family with Belgian Blue inheritance. Regions identified underlying QTL need to be assessed in other populations. Although the myostatin gene has a considerable effect, other loci with more subtle effects are involved in the expression of the phenotype.  相似文献   

17.
Twinning in cattle is a complex trait that is associated with economic loss and health issues such as abortion, dystocia, and reduced calf survival. Twinning-rate QTL have been detected previously on BTA5 in the North American Holstein and Norwegian dairy cattle populations and in a USDA herd selected for high twinning rate. In previous work with the North American Holstein population, the strongest evidence for a QTL was obtained from analysis of an extended, multiple-generation family. Using additional animals, an increased density of SNP marker association tests, and a combined linkage and linkage disequilibrium mapping method, we refined the position of this QTL in the North American Holstein population. Two sets of twinning-rate predicted transmitting abilities estimated during 2 different time periods in the North American dairy cattle population were used to provide validation of results. A total of 106 SNP and 3 microsatellites were used to scan the genomic region between 5 and 80 Mb on BTA5. Combined linkage-linkage disequilibrium analysis identified significant evidence for QTL within the 25- to 35-Mb and 64- to 70-Mb regions of BTA5. The IGF-1 gene (IGF1) was examined as a positional candidate gene and an SNP in intron 2 of IGF1 was significantly associated with twinning rate by using both data sets (P = 0.003 and P = 1.05 x 10(-6)). Replication of this association in other cattle populations will be required to examine the extent of linkage disequilibrium with the underlying quantitative trait nucleotide across breeds.  相似文献   

18.
We constructed a pig F2 resource population by crossing a Meishan sow and a Duroc boar to locate economically important trait loci. The F2 generation was composed of 865 animals (450 males and 415 females) from four F1 males and 24 F1 females and was genotyped for 180 informative microsatellite markers spanning 2,263.6 cM of the whole pig genome. Results of the genome scan showed evidence for significant quantitative trait loci (<1% genomewise error rate) affecting weight at 30 d and average daily gain on Sus scrofa chromosome (SSC) 6, carcass yield on SSC 7, backfat thickness on SSC 7 and SSC X, vertebra number on SSC 1 and SSC 7, loin muscle area on SSC 1 and SSC 7, moisture on SSC 13, intramuscular fat content on SSC 7, and testicular weight on SSC 3 and SSC X. Moreover, 5% genomewise significant QTL were found for birth weight on SSC 7, average daily gain on SSC 4, carcass length on SSC 6, SSC 7, and SSC X and lightness (L value) on SSC 3. We identified 38 QTL for 28 traits at the 5% genomewise level. Of the 38 QTL, 24 QTL for 17 traits were significant at the 1% genomewise level. Analysis of marker genotypes supported the breed of origin results and provided further evidence that a suggestive QTL for circumference of cannon bone also was segregating within the Meishan parent. We identified genomic regions related with growth and meat quality traits. Fine mapping will be required for their application in introgression programs and gene cloning.  相似文献   

19.
Quantitative trait loci (QTL) in Danish Jersey and Danish Red cattle were independently mapped by least squares regression analysis. For Jersey breed, five grandsire families were genotyped for 186 markers on 16 chromosomes (BTAs). Eight traits analysed were milk yield (MY), fat percentage (FP), protein percentage (PP), clinical mastitis (CM), somatic cell score (SCS), maternal stillbirth, maternal calf size (MCS) and maternal calving difficulty. For Red breed, nine grandsire families were genotyped for 166 markers on 18 BTAs. Six traits analysed were MY, FP, PP, CM, SCS and female fertility. Nine and five QTL were detected in Jersey and Red breed, respectively, in across family tests. In Jersey breed, the results indicate QTL for CM and MCS on BTA 3. Additionally, there is an indication of QTL for MCS and FP on BTA 1 and a tentative evidence for a QTL for MY on BTA 26. There is a high risk of detected QTL being false positives. The detected QTL in Jersey breed indicate interesting results from a breeding perspective, but a practical application should await genome-wide association studies.  相似文献   

20.
In dairy cattle, many studies have reported quantitative trait loci (QTL) on the centromeric end of chromosome 14 that affect milk production traits. One of the candidate genes in this QTL region – thyroglobulin (TG) – was previously found to be significantly associated with marbling in beef cattle. Thus, based on QTL studies in dairy cattle and because of possible effects of this gene on fat metabolism, we investigated the association of TG with milk yield and composition in Holstein dairy cattle. A total of 1279 bulls from the Cooperative Dairy DNA Repository Holstein population were genotyped for a single nucleotide polymorphism in TG used previously in beef cattle studies. Analysis of 29 sire families showed no significant association between TG variants and milk production traits. Within‐sire family analysis suggests that TG is neither the responsible gene nor a genetic marker in association with milk production traits.  相似文献   

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