Cattle Chromosomes Research Articles

Radiation hybrid map of buffalo chromosome 7 detects a telomeric inversion compared to cattle chromosome 6.

Radiation hybrid map of buffalo chromosome 7 detects a telomeric inversion compared to cattle chromosome 6.

The Utility of Chromosome Microdissection in Clinical Cytogenetics: A New Reciprocal Translocation in Sheep

Local sheep breeders and scientists in Italy cooperate and conduct research on the genetic improvement of autochthonous genetic types (AGTs) by various approaches, including a cytogenetic breeding selection since 2011. The Laticauda sheep (Ovis aries, 2n = 54) breed is one of the AGTs reared in the Campania region (southern Italy). Performing cytogenetic analyses, we have detected and described a novel reciprocal translocation in a Laticauda sheep identified as 54,XX t(18;23)(q14;q26). Our data support recurring appeals that suggest the regular performance of cytogenetic analyses for monitoring genetic health of livestock species. In total, 5 cases of reciprocal translocations in sheep are known, including the new case. None of them has any phenotypic effect on the living offspring. However, affected animals are characterized by sterility or have a low fertility which can have an effect on breeding success and on economical balance. Presence and kind of the described novel chromosomal aberration were detected by performing CBA-banding and FISH mapping with telomeric probes. RBA-banding allowed the karyotyping of sheep chromosomes and the identification of aberrant chromosomes and regions involved in the new reciprocal translocation. Whole chromosome painting (WCP) probes received from equivalent chromosomes in cattle and the derivative sheep chromosome 18 confirmed the cytogenetic data. This way, our study underlined both the importance of WCP probes by chromosome microdissection and a new way to use WCP probes directly generated from derivative chromosomes.

Association between single-nucleotide polymorphisms and milk production traits in buffalo.

The aim of this study was to identify single-nucleotide polymorphisms (SNPs) in buffaloes associated with milk yield and content, in addition to somatic cell scores based on the cross-species transferability of SNPs from cattle to buffalo. A total of 15,745 SNPs were analyzed, of which 1562 showed 1% significance and 4742 with 5% significance, which were associated for all traits studied. After application of Bonferroni's correction for multiple tests of the traits analyzed, we found 2 significant SNPs placed on cattle chromosomes BTA15 and BTA20, which are homologous to buffalo chromosomes BBU16 and BBU19, respectively. In this genome association study, we found several significant SNPs affecting buffalo milk production and quality. Furthermore, the use of the high-density bovine BeadChip was suitable for genomic analysis in buffaloes. Although extensive chromosome arm homology was described between cattle and buffalo, the exact chromosomal position of SNP markers associated with these economically important traits in buffalo can be determined only through buffalo genome sequencing.

Comparative FISH mapping of BMPR1B, BMP15 and GDF9 fecundity genes on cattle, river buffalo, sheep and goat chromosomes

One of the main goal in livestock genomic projects isthe preparation of extensive genomic maps that identifyloci affecting economically important traits. For this rea-son, the aim of this study was to compare several physi-cal maps using bovine artificial chromosomes (BAC) clonescontaining genes related to fecundity genes. Fluorescent

Modeling tenderness for genetic and quantitative trait loci analyses1

Tenderness is the one of the most important attributes of beef with regards to the intent of consumers to repurchase. Beef tenderness is frequently measured objectively as Warner-Bratzler shear force. However, to better understand the genetics underlying tenderness, better descriptors were derived herein. Two traits, adjusted shear force and aging rate, were calculated to incorporate measures of Warner-Bratzler shear force repeated over aging time of 2 muscles, longissimus dorsi (LD) and semitendinosus (ST). Analysis of these traits indicated that the shear forces of the 2 muscles are lowly correlated and aging rate, as calculated, was not correlated with adjusted shear force. Breed, SNP, and QTL effects were analyzed for the 4 traits (2 traits × 2 muscles). For adjusted shear force, the QTL were located on cattle chromosomes BTA 5, 18, 25, and 29. With the exception of the QTL on BTA 5, the adjusted shear force QTL were observed for either the LD or the ST but not both muscles. The QTL for aging rate were located on BTA 1, 4, 7, 11, 13, 19, and 20.

Analysis of cattle olfactory subgenome: the first detail study on the characteristics of the complete olfactory receptor repertoire of a ruminant

BackgroundMammalian olfactory receptors (ORs) are encoded by the largest mammalian multigene family. Understanding the OR gene repertoire in the cattle genome could lead to link the effects of genetic differences in these genes to variations in olfaction in cattle.ResultsWe report here a whole genome analysis of the olfactory receptor genes of Bos taurus using conserved OR gene-specific motifs and known OR protein sequences from diverse species. Our analysis, using the current cattle genome assembly UMD 3.1 covering 99.9% of the cattle genome, shows that the cattle genome contains 1,071 OR-related sequences including 881 functional, 190 pseudo, and 352 partial OR sequences. The OR genes are located in 49 clusters on 26 cattle chromosomes. We classified them into 18 families consisting of 4 Class I and 14 Class II families and these were further grouped into 272 subfamilies. Comparative analyses of the OR genes of cattle, pigs, humans, mice, and dogs showed that 6.0% (n = 53) of functional OR cattle genes were species-specific. We also showed that significant copy number variations are present in the OR repertoire of the cattle from the analysis of 10 selected OR genes.ConclusionOur analysis revealed the almost complete OR gene repertoire from an individual cattle genome. Though the number of OR genes were lower than in pigs, the analysis of the genetic system of cattle ORs showed close similarities to that of the pig.

Transcription of a protein-coding gene on B chromosomes of the Siberian roe deer (Capreolus pygargus)

BackgroundMost eukaryotic species represent stable karyotypes with a particular diploid number. B chromosomes are additional to standard karyotypes and may vary in size, number and morphology even between cells of the same individual. For many years it was generally believed that B chromosomes found in some plant, animal and fungi species lacked active genes. Recently, molecular cytogenetic studies showed the presence of additional copies of protein-coding genes on B chromosomes. However, the transcriptional activity of these genes remained elusive. We studied karyotypes of the Siberian roe deer (Capreolus pygargus) that possess up to 14 B chromosomes to investigate the presence and expression of genes on supernumerary chromosomes.ResultsHere, we describe a 2 Mbp region homologous to cattle chromosome 3 and containing TNNI3K (partial), FPGT, LRRIQ3 and a large gene-sparse segment on B chromosomes of the Siberian roe deer. The presence of the copy of the autosomal region was demonstrated by B-specific cDNA analysis, PCR assisted mapping, cattle bacterial artificial chromosome (BAC) clone localization and quantitative polymerase chain reaction (qPCR). By comparative analysis of B-specific and non-B chromosomal sequences we discovered some B chromosome-specific mutations in protein-coding genes, which further enabled the detection of a FPGT-TNNI3K transcript expressed from duplicated genes located on B chromosomes in roe deer fibroblasts.ConclusionsDiscovery of a large autosomal segment in all B chromosomes of the Siberian roe deer further corroborates the view of an autosomal origin for these elements. Detection of a B-derived transcript in fibroblasts implies that the protein coding sequences located on Bs are not fully inactivated. The origin, evolution and effect on host of B chromosomal genes seem to be similar to autosomal segmental duplications, which reinforces the view that supernumerary chromosomal elements might play an important role in genome evolution.

Reference-assisted chromosome assembly

One of the most difficult problems in modern genomics is the assembly of full-length chromosomes using next generation sequencing (NGS) data. To address this problem, we developed "reference-assisted chromosome assembly" (RACA), an algorithm to reliably order and orient sequence scaffolds generated by NGS and assemblers into longer chromosomal fragments using comparative genome information and paired-end reads. Evaluation of results using simulated and real genome assemblies indicates that our approach can substantially improve genomes generated by a wide variety of de novo assemblers if a good reference assembly of a closely related species and outgroup genomes are available. We used RACA to reconstruct 60 Tibetan antelope (Pantholops hodgsonii) chromosome fragments from 1,434 SOAPdenovo sequence scaffolds, of which 16 chromosome fragments were homologous to complete cattle chromosomes. Experimental validation by PCR showed that predictions made by RACA are highly accurate. Our results indicate that RACA will significantly facilitate the study of chromosome evolution and genome rearrangements for the large number of genomes being sequenced by NGS that do not have a genetic or physical map.

Cytogenetic and molecular analysis of chromosome instability in cattle with reproductive problems / Cytogenetyczna i molekularna analiza niestabilności chromosomów u bydła z problemam w rozrodzie

Summary. The cytogenetic and molecular analysis of cattle chromosome instability revealed excessive fragility of chromosome X in q11, q24, q31 and p13 regions in cows with reproductive problems. The highest frequency of structural defects was found in BTAXp13 region containing FRM1 gene locus with unstable trinucleotide CGG repeats which were mapped by in situ PCR method. The results obtained suggest that chromosome X structural instability may be a cause of defective expression of genes related with fertility and it leads to a decrease of reproductive efficiency. The present outcomes can be used in further studies on the cytogenetic and molecular substructure of chromosome instability phenomenon and their phenotypic effects in cattle.

Analysis of Chromosome and Karyotype in Bali Cattle and Simmental-bali (Simbal) Crossbreed Cattle

Chromosome analysis is very important part for the initial analysis of genetics. Some genetics abnormalities can be detected at the chromosome level and are usually associated with the inherited diseases. Accurate and prompt information need to be obtained for the purposes of the prevention of the genetics abnormalities genetics risk. This study was aimed to find out and to analyze the different size and morphological chromosome of Bali cattle and its crosses with Simmental cattle (Simbal cattle). Ten Simbal cattle (5 male and 5 female) and 5 female Bali cattle were used in this study. Five milliliter blood was collected using venous puncture through the jugular vein of each cattle. Chromosome was derived from white blood cells (lymphocyte) of peripheral blood. The Bali cattle and Simbal cattle have diploid chromosome (2n) of 60, with 29 pair of autosomes and one pair of sex chromosome. All autosomes are acrocentric with centromere index of 25.13 to 29.52% for Simbal cattle and 21.61 to 24.84% for Bali cattle. Sex chromosomes ware sub-metacentric in Simbal cattle either male or female and metacentric in female Bali cattle. Average length of chromosomes of female Simbal, male Simbal and female Bali cattle were 0.29 +/- 0.04 micron, 0.30 +/- 0.05 micron and 0.24 +/- 0.02 micron, respectively. Chromosome size of female Bali cattle was smaller than Simbal cattle.

Y are you not pregnant: Identification of Y chromosome segments in female cattle with decreased reproductive efficiency,,,

Reproductive efficiency is of economic importance in commercial beef cattle production, since failure to achieve pregnancy reduces the number of calves marketed. Identification of genetic markers with predictive merit for reproductive success would facilitate early selection of females and avoid inefficiencies associated with sub-fertile cows. To identify regions of the genome harboring variation affecting reproductive success, we applied a genome-wide association approach based on the >700,000 SNP marker assay. To include the largest number of individuals possible under the available budget, cows from several populations were assigned to extremes for reproductive efficiency, and DNA was pooled within population and phenotype before genotyping. Surprisingly, pools prepared from DNA of low reproductive cattle returned fluorescence intensity data intermediate between fertile females and males for SNP mapped to the Y chromosome (i.e., male sex chromosome). The presence of Y-associated material in low reproductive heifers or cows was confirmed by Y-directed PCR, which revealed that 21 to 29% of females in the low reproductive category were positive by a Y chromosome PCR test normally used to sex embryos. The presence of the Y chromosome anomaly was further confirmed with application of additional Y-specific PCR amplicons, indicating the likelihood of the presence of some portion of male sex chromosome in female cattle in various beef cattle herds across the U.S. Discovery of this Y anomaly in low reproductive females may make an important contribution to management of reproductive failures in beef cattle operations.

First steps: bovine genomics in historical perspective

The vision of Morris Soller was instrumental in launching the field of bovine genomics. This study is a review of the early years of bovine gene mapping leading up to the sequencing and assembly of the bovine genome in 2009. A historical perspective of parasexual, linkage and physical mapping is provided with a focus on the contribution of these maps to the eventual assignment and orientation of genes and sequence to cattle chromosomes.

Advanced comparative cytogenetic analysis of X chromosomes in river buffalo, cattle, sheep, and human

Based on a recently generated comprehensive gene map for Ovis aries chromosome X (OARX) with an approximately even locus distribution, we assigned selected bacterial artificial chromosome (BAC) probes corresponding to these OARX loci to Bubalus bubalis (BBU) and Bos taurus (BTA) by comparative fluorescence in-situ hybridization (FISH) to improve cytogenetically the X chromosome maps in these species. Twenty-five added loci in BBUX and BTAX, respectively, contribute to a more detailed description of the cytogenetic organization of these chromosomes. Further seven loci were identified in OARX and two DNA probes were assigned to X and Y chromosomes in river buffalo, cattle, and sheep, respectively, and thus identified loci in the pseudoautosomal region. The additional assignments double the number of cytogenetic loci in BBUX and increase their number in BTAX and OARX. The larger quantity of cytogenetic anchors allows a more precise morphological comparison of bovid X chromosomes among each other and with the Homo sapiens (HSA) X chromosome. The anchor loci confirm and refine syntenic fragments in HSAX and identify several evolutionary breakpoints between the compared chromosomes. The cytogenetic assignments in BBUX, BTAX, and OARX represent useable anchors for the ongoing genome sequence assembly in Bovidae.

Chromosome evolution of the Malayan gaur (Bos gaurus hubbacki)

A GTG-banding comparison between the chromosomes of gaur (Bos gaurus hubbacki, BGA, 2n = 56) and those of domestic cattle (Bos taurus, BTA, 2n = 60) was performed to establish chromosome homoeologies or differences between the two species. The two biarmed chromosomes of gaur (BGA1 and BGA2) were originated by centric fusion translocations between homoeologous cattle chromosomes 1/29 (BGA1) and 2/28 (BGA2). High resolution GTG-banding comparison between BGA1 and BTA1/BTA29 revealed that BGA1q differentiated from BTA1 by a paracentric inversion of a large and proximal chromosome region (BTA1q13-q32). To our knowledge, this is the first case of a bovid biarmed chromosome originated by centric fusion and paracentric inversion during karyotype evolution. The CBG-banding pattern showed clear C-bands in all autosomes, although the two biarmed pairs showed smaller C-bands, especially in BGA2. The results were discussed on the basis of previous results obtained in other bovid species, including the carriers of rob...

Sex determination of cattle meat by polymerase chain reaction amplification of the amelogenin AMELXAMELY gene

Aim: The objective of this study was to develop a simplified, efficient, and accurate protocol for sexing of cattle meat based on the amelogenin (AMELX/AMELY) gene using PCR technique which is superior to earlier work in terms of band patterns. Materials and Methods: Based on the amelogenin gene located on the conservation region of X and Y chromosomes, a pair of primers was designed and the system of PCR was established to amplify a 241-bp fragment from the X chromosome in female cattle, and a 241-bp fragment from X chromosome and 178-bp fragment from the Y chromosome in male cattle, respectively. The accuracy and specificity of the primers was assessed using DNA template extracted from cattle meat samples of known sex. The protocol was subjected to a blind test showed 100% concordance, proving its accuracy and reliability. Results: PCR products of cattle meat samples after electrophoresis showed two bands (241, 178-bp) for tissue from male while female tissue resulted in only one (241-bp) band. Conclusions: Our findings show that the PCR assay based on the amelogenin gene is reliable for sex determination in cattle meat.

Evaluation of Single Nucleotide Polymorphisms (SNPs) Genotyped by the Illumina Bovine SNP50K in Cattle Focusing on Hanwoo Breed.

In the present study, we evaluated the informativeness of SNPs genotyped by the Illumina Bovine SNP50K assay in different cattle breeds. To investigate these on a genome-wide scale, we considered 52,678 SNPs spanning the whole autosomal and X chromosomes in cattle. Our study samples consists of six different cattle breeds. Across the breeds approximately 72 and 6% SNPs were found polymorphic and fixed or close to fix in all the breeds, respectively. The variations in the average minor allele frequency (MAF) were significantly different between the breeds studied. The level of average MAF observed in Hanwoo was significantly lower than the other breeds. Hanwoo breed also displayed the lowest number of polymorphic SNPs across all the chromosomes. More importantly, this study indicated that the Bovine SNP50K assay will have reduced power for genome-wide association studies in Hanwoo as compared to other cattle breeds. Overall, the Bovine SNP50K assay described in this study offer a useful genotyping platform for mapping quantitative trait loci (QTLs) in the cattle breeds. The assay data represent a vast and generally untapped resource to assist the investigation of the complex production traits and the development of marker-assisted selection programs.

Genome-Wide Scan Identifies Loci Associated with Classical BSE Occurrence

Classical bovine spongiform encephalopathy (BSE) is an acquired prion disease that is invariably fatal in cattle and has been implicated as a significant human health risk. Sequence variations in the coding region of the prion gene (PRNP) have been associated with acquired transmissible spongiform encephalopathy (TSE) susceptibility in mammals; however, this is not the case in cattle. It has been hypothesized that genes, in addition to the prion gene, contribute to genetic susceptibility of acquired TSEs. Accordingly, genetic studies of classical BSE in cattle identified loci other than PRNP that are associated with disease incidence. The objective of this study was to utilize a genome-wide association study to test for genetic loci associated with classical BSE. The samples include 143 BSE affected (case) and 173 unaffected half sib (control) animals collected in the mid 1990s in Southern England. The data analysis identifies loci on two different chromosomes associated with BSE disease occurrence. Most notable is a single nucleotide polymorphism on chromosome 1 at 29.15 Mb that is associated with BSE disease (p = 3.09E-05). Additionally, a locus on chromosome 14, within a cluster of SNPs showed a trend toward significance (p = 5.24E-05). It is worth noting that in a human vCJD study markers on human chromosome 8, a region with shared synteny to the region identified on cattle chromosome 14, were associated with disease. Further, our candidate genes appear to have plausible biological relevance with the known etiology of TSE disease. One of the candidate genes is hypothetical gene LOC521010, similar to FK506 binding protein 2 located on chromosome 1 at 29.32 Mb. This gene encodes a protein that is a member of the immunophilin protein family and is involved in basic cellular processes including protein folding. The chromosomal regions identified in this study and candidate genes within these regions merit further investigation.

The gene ontology and electro localization of ovine skin derived EST-SSR markers

Abstract: In order to study the potential gene function of ovine EST-SSR markers, nine original EST of Ovine Skin Derived polymorphic EST-SSR loci, which were developed in an early study by our lab, were ontology annotated and Electro localized. The results revealed that the original ESTs of the six loci had high homology with known genes and three of them probably played an important role in wool traits. Compared with its cDNA library, 8 loci were located on chromosomes of cattle. The homology of chromosomes between cattle and sheep was estimated based on the similarity coefficients calculated by positioning markers. Additionally, NJ clustering tree was establishedto serve for electro localization of ovine EST-SSR markers. Finally, 8 EST-SSR markers were successfully positioned on ovine chromosomes. The results from this study not only provide references for further studies on genetic mapping, in silico cloning of key genes for wool traits, but also are helpful to the researchs of chromosome evolution in animal.

Multisite haplotype on cattle chromosome 3 is associated with quantitative trait locus effects on lactation traits

The goal of this study was to identify candidate genes and DNA polymorphisms for quantitative trait loci (QTL) affecting milk yield (MY), fat yield (FY), and protein yield (PY) previously mapped to bovine chromosome 3 (BTA3). To accomplish this, 373 half-siblings sired by three bulls previously shown to be segregating for lactation trait QTL, and 263 additional sires in the U.S. Dairy Bull DNA Repository (DBDR) were genotyped for 2,500 SNPs within a 16.3 Mbp QTL critical region on BTA3. Targeted resequencing of ∼1.8 Mbp within the QTL critical region of one of the QTL heterozygous sires identified additional polymorphisms useful for association studies. Twenty-three single nucleotide polymorphisms (SNPs) within a fine-mapped region were associated with effects on breeding values for MY, FY, or PY in DBDR sires, of which five SNPs were in strong linkage disequilibrium in the population. This multisite haplotype included SNPs located within exons or promoters of four tightly linked genes: RAP1A, ADORA3, OVGP1, and C3H1orf88. An SNP within RAP1A showed strong evidence of a recent selective sweep based on integrated haplotype score and was also associated with breeding value for PY. Because of its known function in alveolar lumen formation in the mammary gland, RAP1A is thus a strong candidate gene for QTL effects on lactation traits. Our results provide a detailed assessment of a QTL region that will be a useful guide for complex traits analysis in humans and other noninbred species.

Discovery, validation and characterization of 1039 cattle single nucleotide polymorphisms

We identified approximately 13 000 putative single nucleotide polymorphisms (SNPs) by comparison of repeat-masked BAC-end sequences from the cattle RPCI-42 BAC library with whole-genome shotgun contigs of cattle genome assembly Btau 1.0. Genotyping of a subset of these SNPs was performed on a panel containing 186 DNA samples from 18 cattle breeds including 43 trios. Of 1039 SNPs confirmed as polymorphic in the panel, 998 had minor allele frequency > or =0.25 among unrelated individuals of at least one breed. When Btau 4.0 became available, 974 of these validated SNPs were assigned in silico to known cattle chromosomes, while 41 SNPs were mapped to unassigned sequence scaffolds, yielding one SNP every approximately 3 Mbp on average. Twenty-four SNPs identified in Btau 1.0 were not mapped to Btau 4.0. Of the 1015 SNPs mapped to Btau 4.0, 959 SNPs had nucleotide bases identical in Btau 4.0 and Btau 1.0 contigs, whereas 56 bases were changed, resulting in the loss of the in silico SNP in Btau 4.0. Because these 1039 SNPs were all directly confirmed by genotyping on the multi-breed panel, it is likely that the original polymorphisms were correctly identified. The 1039 validated SNPs identified in this study represent a new and useful resource for genome-wide association studies and applications in animal breeding.