Nucleotide sequence and variation of IGF2 gene exon 6 in Bos taurus and Bos indicus cattle

The major assumption of this study is that polymorphism of a gene could be used to investigate its allele-specific expression as well as its methylation and imprinting status. Therefore, the aim of this study was to analyze the polymorphism of the coding region of the bovine IGF2 gene and to determine the sequence of its gene exon 6 in Bos taurus and Bos indicus cattle. A single nucleotide "C" deletion/insertion polymorphism was found in both cattle subspecies and a G/T transversion (RFLP-MboII) in the Bos indicus IGF2 gene. A 407-bp fragment of bovine IGF2 exon 6 was sequenced and the sequences (including variable nucleotides) were deposited in the GenBank database. A comparative analysis was performed for this fragment from different species; 99.5% identity was found between Bos taurus and Bos indicus cattle.     

Characterization and genetic analysis of bovine αs1-casein I variant

The aim of this study was to identify the molecular genetic origin underlying the I variant of α_s1-casein and to develop a DNA-based test for this polymorphism as a tool for genetic analyses independent of milk sample testing. All coding exons and flanking regions of the α _{s 1} -casein gene were sequenced in DNA samples from cattle of known α _{s 1} -casein genotypes ( BI , CI , II , CC ), determined by isoelectric focusing of milk samples. A nucleotide substitution (A>T) in exon 11 (g.19836A>T) leads to the exchange of Glu with Asp at amino acid position 84 of the mature protein (p.Glu84Asp) and perfectly co-segregated with the presence of the α_s1-casein I variant in the milk of the analysed animals. Genotyping of a total of 680 DNA samples from 31 Bos taurus and Bos indicus cattle breeds and from Bos grunniens , Bison bison and Bison bonasus by restriction fragment length polymorphism analysis revealed the occurrence of Asp at position 84 at low frequencies in Bos taurus and Bos indicus breeds and established its origin from the α _s1-casein C variant (p.Glu192Gly). Ten different intragenic haplotypes in the gene region from intron 8 to intron 12 were observed by sequencing, of which two occurred in Bison bison and one in Bison bonasus only. Using available casein gene complex information, an association of Asp at position 84 to β-casein A ² and κ-casein B was shown in the Bos indicus breed Banyo Gudali . Taken together, we can postulate that the α _s1-casein variant I is caused by a non-synonymous nucleotide substitution in exon 11 of the gene and that it originated within Bos indicus and spread to Bos taurus subsequently.     

Assignment of the growth hormone receptor gene to bovine chromosome 20 using linkage analysis and somatic cell mapping

A polymorphism was identified in the bovine growth hormone receptor ( GHR ) gene by digesting polymerase chain reaction (PCR) products with the restriction enzyme Alul. Two alleles were segregating in cattle of Bos indicus descent, but one allele appears to be fixed in Bos taurus cattle. GHR was localized to bovine chromosome 20 using bovine-rodent hybrid cell lines and linkage analysis.     

Bovine gene polymorphisms related to fat deposition and meat tenderness

Leptin, thyroglobulin and diacylglycerol O-acyltransferase play important roles in fat metabolism. Fat deposition has an influence on meat quality and consumers' choice. The aim of this study was to determine allele and genotype frequencies of polymorphisms of the bovine genes, which encode leptin (LEP), thyroglobulin (TG) and diacylglycerol O-acyltransferase (DGAT1). A further objective was to establish the effects of these polymorphisms on meat characteristics. We genotyped 147 animals belonging to the Nelore (Bos indicus), Canchim (5/8 Bos taurus + 3/8 Bos indicus), Rubia Gallega X Nelore (1/2 Bos taurus + 1/2 Bos indicus), Brangus Three-way cross (9/16 Bos taurus + 7/16 Bos indicus) and Braunvieh Three-way cross (3/4 Bos taurus + 1/4 Bos indicus) breeds. Backfat thickness, total lipids, marbling score, ribeye area and shear force were fitted, using the General Linear Model (GLM) procedure of the SAS software. The least square means of genotypes and genetic groups were compared using Tukey's test. Allele frequencies vary among the genetic groups, depending on Bos indicus versus Bos taurus influence. The LEP polymorphism segregates in pure Bos indicus Nelore animals, which is a new finding. The T allele of TG is fixed in Nelore, and DGAT1 segregates in all groups, but the frequency of allele A is lower in Nelore animals. The results showed no association between the genotypes and traits studied, but a genetic group effect on these traits was found. So, the genetic background remains relevant for fat deposition and meat tenderness, but the gene markers developed for Bos taurus may be insufficient for Bos indicus.     

雷琼牛GH基因第五外显子遗传多样性及其分化

对16头雷琼牛GH基因第5外显子序列进行分析,发现了1个变异位点,定义了2种单倍型。引用巴州牦牛2个个体GH基因同源区序列并结合GenBank中牛属普通牛、其它瘤牛和牦牛3个种群与水牛1个远缘种GH基因同源区序列,分别采用邻接（NJ）法和最大简约（MP）法构建分子系统发育树,得到基本一致的拓扑结构,结果显示GH基因的分化早于雷琼牛（瘤牛）、其它瘤牛、普通牛、牦牛和水牛的分化,瘤牛物种内存在多型,同时证实了GH基因第5外显子区有着较高的突变率。     

Comparative gene frequencies of nucleoside phosphorylase from cattle of Bos taurus and Bos indicus derivation in Brazil

1. Two nucleoside phosphorylase (NP) phenotypes were detected in 844 animals from four distinct genetic groups of Bos taurus and Bos indicus derivation. 2. Bos indicus breeds like Guzerat (Kankrej), Gir, Nellore (Ongole) and Indubrazil presented an NP-H frequency of 1.00, 0.928, 0.776 and 0.754 respectively, while the Canchim breed, a Bos taurus-Bos indicus crossbred cattle (5/8 Charolais-3/8 Zebu) presented a frequency of 0.372. 3. The high frequency detected from the NP-H allele in the Bos indicus breeds strongly suggests that this enzyme is a genetic marker for cattle and that it probably has a very high frequency in all Indian breeds.     

Complete mitochondrial genomes of Bos taurus and Bos indicus provide new insights into intra-species variation, taxonomy and domestication

The taurine and zebuine cattle breeds comprise the majority of the world cattle population but their taxonomic status is still controversial. The two forms of cattle are currently classified as Bos taurus and Bos indicus species and are differentiated primarily by the presence or absence of a hump. However, these two species hybridize readily, producing fully fertile offspring. We have determined and analyzed complete B. taurus and B. indicus mitochondrial genome sequences to investigate the extent of sequence divergences and to study their taxonomic status by molecular dating. The sequences encompassed 16,338 and 16,339 nucleotides, respectively, and differed at 237 positions. Estimated divergence times indicated that the two cattle lineages separated 1.7-2.0 million years ago. Combined phylogenetic analyses of 18 new and 130 previously reported extant B. taurus and B. indicus control region sequences with data from 32 archaeological specimens of the extinct wild aurochs (Bos primigenius) identified four major maternal lineages. B. primigenius haplotypes were present in all but the B. indicus lineage, and one B. taurus sequence clustered with B. primigenius P haplotypes that were not previously linked with domestic cattle. The B. indicus cluster and a recently reported new B. primigenius haplotype that represents a new lineage were approximately equidistant from the B. taurus cluster. These data suggest domestications from several differentiated populations of B. primigenius and a subspecies status for taurine (B. primigenius taurus) and zebuine (B. primigenius indicus) cattle.     

Analysis of Genetic Variation at the Prolactin-RsaI (PRL-RsaI) Locus in Indian Native Cattle Breeds (Bos indicus)

This study assessed the distribution pattern of allelic variants at the prolactin-RsaI locus in 23 Indian native cattle breeds (Bos indicus). PCR-RFLP genotyping of a 156?bp fragment of prolactin (PRL) in exon 3 revealed the predominance of the heterozygous AB genotype (mean frequency 0.58) irrespective of utility type (dairy, dual, draft), geographic region (northern, central, southern), and coat color (red, gray) of the breeds analyzed. The overall frequencies of homozygous AA (0.22) and BB (0.20) genotypes were in a similar range. The PRL (A) and PRL (B) alleles exhibited similar gene frequencies (means 0.52 and 0.48, respectively). The existing profile of the PRL-RsaI gene locus in a large set of Indian native cattle breeds was different from that of Bos taurus and cattle breeds of other countries, where either the BB genotype and PRL (B) allele or the AA genotype and PRL (A) allele have been reported to be more prevalent.     

Comparative analysis of GDF 8 (myostatin) in Bos indicus and Bos taurus.

We report the myostatin gene sequence of Bos indicus cattle in comparison to Bos taurus. B. indicus genomic sequence was obtained by overlapping PCR amplification of genomic DNA. Exon splice sites were confirmed by mRNA sequencing. There were 5 exonic single nucleotide polymorphisms (SNP) only one of which was a non-synonymous mutation that resulted in a serine to asparagine (S214N) amino acid substitution. The B. indicus gene has two insertions of 16 and 12 bases in the first intron. In addition, SNPs in the 3' UTR and intronic regions are also reported.     

Reproductive cycles in Bos indicus cattle

Several studies using transrectal ovarian ultrasonic scanning in Bos taurus (B. taurus) cattle and more recently in Bos indicus (B. Indicus) females evaluated the reproductive cycles of heifers and cows under different conditions. In general, B. indicus cattle have more follicles and more follicular waves during the estrous cycle and ovulate from smaller follicles than B. taurus. Consequently B. indicus females have smaller corpora lutea and it is assumed circulating concentrations of estradiol and progesterone are also less. However, these findings may vary depending on the nutritional status and regimen in which the animals are managed. Moreover, there are significant differences between B. taurus and B. indicus regarding follicle size at the time of deviation of the dominant follicle. These differences in ovarian function between B. indicus and B. taurus, e.g. greater antral follicle population are, probably, the main reasons for the great success of in vitro embryo production programs in Zebu cattle, especially in Brazil.     

A polymorphism in randomly amplified DNA that differentiates the Y chromosomes of Bos indicus and Bos taurus

A small number of west African Bos taurus cattle breeds, including the N'Dama, constitute a valuable genetic resource by virtue of their ability to remain productive under trypanosomiasis challenge. However, introgression of Bos indicus genes into the trypanotolerant breeds, particularly by introduction of zebu bulls, is a threat to this resource. This work describes the characterization and cloning of a bovine randomly amplified polymorphic DNA (RAPD) that is generated in polymerase chain reaction (PCR) with the 10 base primer ILO1065 from Bos indicus male templates, but not from B. taurus male templates or female templates of either type. Male-specific sequences with homology to the RAPD also occur in B. taurus breeds. This suggests that the polymorphism may be due to base substitution(s) in an ILO1065 priming site, or insertion/deletion events either affecting priming sites or occurring between sites on the cattle Y chromosome. We have shown that cattle, whether of B. indicus or B. taurus phenotype, which possess a typically B. indicus metaphase Y chromosome on the basis of QFQ banding, have a B. indicus ILO1065-generated genotype. The ILO1065-primed RAPD can be used in a simple dot blot assay as a probe of RAPD-PCR products, to provide a convenient, reliable and effective means of detecting introgression of zebu genes in B. taurus cattle populations.     

Superovulation and embryo transfer in Bos indicus cattle

Compared to Bos taurus breeds, Bos indicus breeds of cattle present several differences in reproductive physiology. Follicular diameter at deviation and at the time of ovulatory capability are smaller in B. indicus breeds. Furthermore, B. indicus breeds have a greater sensitivity to gonadotropins, a shorter duration of estrus, and more often express estrus during the night. These differences must be considered when setting up embryo transfer programs for B. indicus cattle. In recent studies, we evaluated follicular dynamics and superovulatory responses in B. indicus donors with the objective of implementing fixed-time AI protocols in superstimulated donors. Protocols using estradiol and progesterone/progestrogen releasing devices to control follicular wave emergence were as efficacious as in B. taurus cattle, allowing the initiation of superstimulatory treatments (with lower dosages of FSH than in B. taurus donors) at a self-appointed time. Furthermore, results presented herein indicate that delaying the removal of progesterone/progestogen-releasing devices, combined with the administration of GnRH or pLH 12 h after the last FSH injection, results in synchronous ovulations, permitting the application of fixed-time AI of donors without the necessity of estrus detection and without compromising the results.     

Identical marker alleles in Podolic cattle (Bos taurus) and Indian zebu (Bos indicus)

In the context of biochemical marker research and in order to add new information on native breeds, the present work focuses on a local Southern Italy cattle, namely Italian Podolic. We provide the complete structural characterisation of alpha-lactalbumins and beta-globin chains isolated from Podolic cattle (Bos taurus). Given the unavailability of the complete sequence for alpha-lactalbumin A of taurine cattle in the literature, we intended to check its structure in order to ascertain the absence of any possible silent mutation. Screening the Podolic cattle, we found a new beta-globin variant not detectable by conventional methods. The presence of such a new variant might be helpful in the study of the Podolic population genetic structure and for a better knowledge of the gene pool per se, and in comparison with the other breeds. Structural analyses showed that the new beta-globin Podolic variant exhibited the same sequence as beta-globin Azebu. The alpha-lactalbumin A was the same as that isolated from zebu cattle (Bos indicus). The results are discussed in relation to the possible involvement of the two markers in the debate on the origin of the Podolic breed.     

Importance of sperm genotype (indicus versus taurus) for fertility and embryonic development at elevated temperatures

Heat stress has negative effects on bovine reproduction, particularly for European breeds (Bos taurus taurus) that are less thermotolerant than zebu cattle (Bos taurus indicus). Here, the evidence that spermatozoa and oocyte both contribute to early embryonic resistance to heat shock is demonstrated. In addition, the use of reproductive biotechnologies to improve bovine thermotolerance, are outlined by comparing data from taurus, indicus and crossbred genotypes.     

Somatic cell mapping, polymorphism, and linkage analysis of bovine prolactin-related proteins and placental lactogen.

The bovine prolactin gene family includes novel members expressed in the fetal placenta that are distinct from placental lactogen. In this study, we investigated the genetic organization of four members of this gene family (PRP1, PRP3, PRP6, and PRP10) as well as placental lactogen (PL). Using a bovine-rodent hybrid somatic cell panel, all five genes were assigned to bovine chromosome 23, which contains prolactin and the major histocompatibility group (BOLA). Restriction fragment length polymorphisms were detected by all probes in breeding populations with the restriction enzyme MspI, whereas no polymorphisms were detected with BamHI. EcoRI, HindIII, TaqI, and PstI produced polymorphic fragments with some but not all of the probes tested. A PRP10 polymorphism, which is apparently the result of a insertion/deletion event, detected polymorphism frequency differences between Bos indicus and Bos taurus. No recombinational events were observed with these probes and prolactin using linkage analysis involving 91 American Holsteins. The bovine prolactin gene family was incorporated into a linkage group containing CYP21. Our studies demonstrate that members of the bovine prolactin gene family have a close physical association with each other, and all members demonstrate genetic variability in the breeding population.     

Mitochondrial DNA variation in cattle of South China: origin and introgression

Ten restriction endonucleases were used to investigate the mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) of 11 native cattle breeds and one cultivated cattle breed in South China. Twenty-three restriction morphs were detected, which can be sorted into five haplotypes. A phylogenetic tree of the haplotypes was constructed by using the 'upgMa' method. Our study showed that haplotype I and II are identical to the zebu (Bos indicus) and taurine (Bos taurus) haplotypes, respectively. Zebu and taurine were the two major origins of cattle populations in South China, and the zebu probably had more influence on the native cattle population than taurine did. Haplotype III is identical to haplotype I of yak (Bos grunniens), which was only detected in the Diqing cattle breed. Haplotype IV was detected for the first time. This haplotype, found only in Dehong cattle, might be from an independent domestication event, probably from another Bos indicus population. Divergence of haplotypes I and IV occurred about 268,000-535,000 years ago, much earlier than the 10,000-year history of cattle husbandry. Our results also suggest a secondary introgession of mtDNA from yak to Diqing cattle.     

Origin and phylogeographical structure of Chinese cattle

Complete mitochondrial D-loop sequences of 231 samples were used to explore the origin and genetic diversity of Chinese cattle. Phylogenetical analysis of these sequences revealed both Bos taurus and Bos indicus mitochondrial types in Chinese cattle. Four of the previously identified mitochondrial DNA lineages (T1–T4) were identified in the Bos taurus type, including lineage T1, which was found for the first time in Chinese cattle. Two lineages (I1 and I2) were identified in the Bos indicus type. Our results support the suggestion that the Yunnan-Guizhou Plateau is the domestication site of Chinese zebu. We also found evidence that Tibetan cattle originated from taurine and zebu cattle. The distribution pattern of Chinese cattle breeds was closely related to the geographical and climatic background. It was possible to divide Chinese cattle in this study into two major groups: northern and southern cattle.