Mapping of bovine prolactin and rhodopsin genes in hybrid somatic cells

Association analysis of single-nucleotide polymorphism in prolactin and its receptor with productive and body conformation traits in Liaoning cashmere goats

The results of this study showed that the single-nucleotide polymorphism (SNP) sites of the PRL and PRLR genes have a certain association with the milk production performance, body size and cashmere performance of Liaoning cashmere goats (LCGs). Through our designed experiment, the potential SNPs of LCG were detected by sequence alignment, and two SNPs were found on two genes. The CC genotype of the PRL gene is the dominant genotype among the three genotypes. The GG genotype of the PRLR gene is the dominant genotype among the two genotypes. At the same time, the two genotypes also have good performance in cashmere production and body size. Through the screening of haplotype combination, the milk fat rate > 7.6 %, the milk protein rate > 5.6 %, the milk somatic cell number < 1500 × 103 mL-1, the cashmere fineness < 15.75 µm, the chest girth > 105 cm, the chest depth > 33 cm, and the waist height > 67.5 cm are considered as screening indexes for comprehensive production performance of Liaoning cashmere goats. It is concluded that the GCGC type is the dominant haplotype combination. According to our research data, we found that the biological indicators of Liaoning cashmere goat milk are higher than the national standards, so we think it is very significant to study the milk production performance of our experiment. Further research can be done on goat milk production and body conformation traits around PRL gene and PRLR gene.

Prolactin gene polymorphism in indigenous and crossbred cattle of north east India

Bovine PRL gene is considered one of the important hereditary components of milk productivity, thus seems to be an excellent candidate gene for milk production traits. The study was conducted to study the distribution pattern of allelic variants at the prolactin-RsaI locus in 210 indigenous cattle of north east India (viz. Manipur, Mizoram, Nagaland, Tripura, Asom and Meghalaya,) and crossbred cattle of Mizoram. PCR-RFLP genotyping of a 156 bp fragment of prolactin (PRL) in exon 3 revealed two different allelic variants. The predominant genotype (s) were AB (0.40) and BB (0.40) in indigenous cattle of Manipur, BB in Mizoram (0.57), AB in indigenous cattle of Nagaland (0.50) and Meghalaya (0.63). Whereas in Tripura and Asom indigenous cattle, AA was the most common genotype (0.40 and 0.60). However, AB (0.80) was markedly higher in crossbred (HF × indigenous) cattle. All the six indigenous cattle populations conforming to equilibrium indicated lack of selection pressure for PRL gene in these cattle population. The most frequent allele was A allele in the indigenous cattle of Nagaland (0.55), Tripura (0.55) and Asom (0.70) and B allele in indigenous cattle of Manipur (0.60) and Mizoram (0.73). Whereas, in Meghalaya indigenous and crossbred cattle, both alleles were present in equal frequencies. The findings of differences in the distributions of allelic and genotype variants of PRL-RsaI locus among the indigenous cattle populations of six states of north east India, suggested the presence of scope for genetic selection for milk production traits.

An association analysis between PRL genotype and milk production traits in Italian Mediterranean river buffalo

This Research Communication describes the association between genetic variation within the prolactin (PRL) gene and the milk production traits of Italian Mediterranean river buffalo (Bufala mediterranea Italiana). High resolution melting (HRM) techniques were developed for genotyping 465 buffaloes. The association of genetic polymorphism with milk production traits was performed and subsequently the effects of parity and calving season were evaluated. Single nucleotide polymorphisms (SNPs) were identified at exons 2 and 5 and at introns 1 and 2. All the SNPs were in Hardy–Weinberg equilibrium, and statistical analysis showed that the polymorphism of intron1 was significantly (P < 0·05) associated with milk yield, milk protein content and peak milk yield. The average contribution of the intron1 genotype (r2intron1) to total phenotypic variance in milk production traits was 0·09, and the TT genotype showed lower values than CC and CT genotypes. A nonsynonymous SNP was identified in exon 2, which resulted in an amino acid change from arginine to cysteine. Moreover, the polymorphism of exon 2 was associated significantly with milk fat content (P < 0·05), and the buffaloes with TT genotype showed higher total fat content than the buffaloes with CT genotype. These findings provide evidence that polymorphisms of the buffalo PRL gene are associated with milk production traits and PRL can be used as a candidate gene for marker-assisted selection in Italian Mediterranean river buffalo breeding.

Polymorphism of the Prolactin Gene and Its Relationship with Milk Production in Gir and Kankrej Cattle

Background:

The aim of this study was to detect allelic and genotypic frequencies of prolactin (PRL) gene in Gir (200) and Kankrej (100) cattle and to analyze milk production traits of tested cattle on their PRL genotypes.

Materials and Methods:

The 156 bp fragment located in exon 3 was amplified using polymerase chain reaction-restriction fragments length polymorphism technique.

Results:

Allele frequencies in the studied breed were A = 0.52 and B = 0.48. Means and standard deviations for milk yield and fat content (%) were 3811.6 ± 462.1 and 3.99 ± 0.18 for the AA genotype, 3514.9 ± 450.8 and 4.16 ± 0.33 for the AB genotype, and 3388.8 ± 423.3 and 4.34 ± 0.11 for the BB genotype, respectively, in Gir cattle. Similarly, for Kankrej cattle, means and standard deviations for milk yield and fat content (%) were 2007.8 ± 246.3 and 4.05 ± 0.16 for the AA genotype, 1846.14 ± 133.4 and 4.10 ± 0.156 for the AB genotype, and 1767.7 ± 186.4 and 4.30 ± 0.178 for the BB genotype, respectively, in Kankrej cattle.

Conclusion:

This study showed differences in milk traits among PRL genotypes of Gir and Kankrej cattle.

Novel SNPs of butyrophilin (BTN1A1) and milk fat globule epidermal growth factor (EGF) 8 (MFG-E8) are associated with milk traits in dairy goat

Butyrophilin (BTN1A1) and milk fat globule epidermal growth factor (EGF) 8 (MFG-E8) genes are both milk fat globule membrane proteins. BTN1A1 plays a key role in the secretion of milk lipid and production which has effects on performance traits, while the MFG-E8 is vital for the development of the mammary gland and phagocytic clearance of apoptotic cells. Therefore, BTN1A1 and MFG-E8 gene are candidate genes for quantitative traits in mammalian animals with respect to milk performance traits. The objective of this study is to investigate variations in goat BTN1A1 and MFG-E8 gene and analyze their associations with growth trait and milk performance. In this study, the goat BTN1A1 gene showed a novel single-nucleotide polymorphism (SNP): XM_001494179:g.8659C>T, resulting in a missense mutation: CTT (Leu)>TTT (Phe) at position 377 aa of the BTN1A1 (526 aa); the goat MFG-E8 gene showed four novel SNPs: NC_007319: g.843delA, 6417delC, 14892T>C and 14996A>C, only the 14892T>C result in a synonymous mutation. The associations between genotypes and production traits were analyzed. Significant statistical results implied that HinfI locus of BTN1A1 gene is associated with milk fat yield (P=0.004), total solid (P=0.002), solid-non fat (P=0.018) and first milk yield (P=0.030). The DA and EcoRV loci of MFG-E8 gene are associated with milk fat yield (DA locus: P=0.000; EcoRV locus: P=0.033) and total solid (DA locus: P=0.002; EcoRV locus: P=0.015) in the Xinong Saanen dairy goat.

Localization and genomic organization of sheep antimicrobial peptide genes

Antimicrobial peptides are an abundant and diverse component of animal innate immunity. Within mammalian species, defensins and cathelicidins are the two principal antimicrobial peptide families. We identified and sequenced ten new sheep genes which encode potential antimicrobial peptides including two beta-defensins and eight cathelicidins. We mapped the two-exon beta-defensin genes to sheep chromosome 26 and the four-exon cathelicidin genes to sheep chromosome 19 using sheep-hamster somatic cell hybrids in conjunction with flow-sorted sheep chromosomes. These assignments confirm homology between sheep, cattle, mouse, and human antimicrobial peptide gene families. Contig construction for the sheep cathelicidin gene family demonstrates that three genes, OaDodeA, OaDodeB, and OaMAP-34, are present head-to-tail in a 14.5 kb region, and that four proline/arginine-rich genes, OaBac5, OaBac7.5, OaBac11, and OaBac6, are arranged head-to-tail in a region covering 30.5 kb. This richly diverse family of sheep cathelicidin peptides is encoded in a gene array which may reflect the mechanism of its evolution.

Microsatellite DNA variation within and among European cattle breeds

Microsatellite markers offer great potential for genetic comparisons within and between populations. We report the analysis of 12 microsatellite loci in six breeds of European cattle. This yielded a wide spectrum of variability with observed heterozygosities ranging from 0.00 to 0.91. Deviations from Hardy-Weinberg equilibrium were noted for some locus-population combinations, particularly at a microsatellite located within the prolactin gene. Also, significant linkage disequilibrium was detected between two microsatellite loci located within the bovine major histocompatibility complex, and this association was maintained across breeds, providing evidence for marker stability during short-term evolution. The mode of mutation was investigated by comparing the observed data with that expected under the infinite alleles model of neutral mutation, and six of the microsatellite loci were found to deviate significantly, suggesting that a stepwise mutation model may be more appropriate. One indication of marker utility is that, when genetic distance estimates were computed, the resultant dendrogram showed concordance with known breed histories.

Anchored reference loci for comparative genome mapping in mammals

Recent advances in gene mapping technologies have led to increased emphasis in developing representative genetic maps for several species, particularly domestic plants and animals. These maps are being compiled with two distinct goals: to provide a resource for genetic analysis, and to help dissect the evolution of genome organization by comparing linkage relationships of homologous genes. We propose here a list of 321 reference anchor loci suitable for comparative gene mapping in mammals and other vertebrate classes. We selected cloned mouse and human functional genes spaced an average of 5-10 centiMorgans throughout their respective genomes. We also attempted to include loci that are evolutionarily conserved and represented in comparative gene maps in other mammalian orders, particularly cattle and the domestic cat. We believe that the map may provide the basis for a unified approach to comparative analysis of mammalian species genomes.

Syntenic assignments of visual transduction genes in cattle

To establish syntenic relationships of phototransduction genes, we have mapped the genes encoding the alpha-, beta-, and gamma-subunits of rod cGMP phosphodiesterase (PDE) (PDEA, PDEB, PDEG), the alpha'-subunit of cone PDE (PDEA2), and the rod cGMP-gated channel (CNCG) to bovine syntenic groups. The rod cGMP PDE alpha-, beta-, and gamma-subunit genes map to bovine syntenic groups U22, U15 (chromosome 6), and U21 (chromosome 19), respectively. The rod cGMP-gated channel gene also maps to syntenic group U15, and the bovine cone alpha'-subunit gene maps to U26 (chromosome 26). With the exception of the cone PDE alpha'-subunit gene, which has not been mapped in other mammals, all of these genes have been assigned to conserved chromosomal regions shared among bovine, human, and mouse. A compilation of currently known syntenic assignments and predictions regarding future assignments of phototransduction genes in human, mouse, and cattle is presented.

Mapping of bovine markers CYP21, PRL, and BOLA DRBP1 by genetic linkage analysis in reference pedigrees

We have analyzed DNA from 13 bovine reference pedigrees using primers specific for microsatellite markers derived from the 21-steroid hydroxylase (CYP21) and prolactin (PRL) genes and the leukocyte antigen (BOLA DRBP1) pseudogene. Linkage was demonstrated between PRL and BOLA DRBP1 (theta = 0.05; Z = 19.6), cyp21 and PRL (theta = 0.13; Z = 6.8), and BOLA DRBP1 and CYP21 (theta = 0.17; Z = 10.4). These results suggest an order BOLA DRBP1-PRL-CYP21, although in a multilocus analysis the alternative order PRL-BOLA DRBP1-CYP21 was also possible. The data confirm and extend the previously established syntenic relationship between these markers on bovine chromosome 23 and provide points of anchorage for further linkage studies in the reference pedigrees described.

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.

Close linkage between bovine prolactin and BoLA-DRB3 genes: genetic mapping in cattle by single sperm typing

The major histocompatibility complex and prolactin (PRL) genes are syntenic in humans and cattle but the genetic distance between these loci has not been determined for either species. In this study, the sperm typing technique was used to measure the recombination frequency between the bovine lymphocyte antigen (BoLA)-DRB3 and PRL loci. A total of 300 sperm were typed from one doubly heterozygous bull for segregation of DRB3 and PRL alleles. Sperm typing was performed using the polymerase chain reaction (PCR) and restriction enzyme cleavage of the PCR products, followed by resolution of the restriction fragments in polyacrylamide gels. Digestion with the restriction endonuclease RsaI allowed the unambiguous discrimination of alleles for both loci. The maximum likelihood estimation of the recombination fraction theta = 0.04, with a 95% confidence interval of 0.01 to 0.07. Close linkage between PRL and DRB3 has important implications for marker-assisted selection in animal breeding since PRL has been shown to be closely linked to a locus that affects milk yield, and BoLA loci influence susceptibility to a number of infectious diseases. Our results demonstrate the general applicability of the sperm typing procedure for gene mapping in species other than humans and provide an example of how parallel efforts to map the genomes of agriculturally important species of animals can have a positive impact on the development of a primary human linkage map.

Mapping HSA 3 loci in cattle: additional support for the ancestral synteny of HSA 3 and 21

Homologs to genes residing on human chromosome 3 (HSA 3) map to four mouse chromosomes (MMU) 3, 6, 9, and 16. In the bovine, two syntenic groups that contain HSA 3 homologs, unassigned syntenic groups 10 (U10) and 12 (U12), have been defined. U10 also contains HSA 21 genes, which is similar to the situation seen on MMU 16, whereas U12 apparently contains only HSA 3 homologs. The syntenic arrangement of other HSA 3 homologs in the bovine was investigated by physically mapping five genes through segregation analysis of a bovine-hamster hybrid somatic cell panel. The genes mapped include Friend-murine leukemia virus integration site 3 homolog (FIM3; HSA 3/MMU 3), sucrase-isomaltase (SI) and glutathione peroxidase 1 (GPX1) (HSA 3/MMU ?), murine leukemia viral (v-raf-1) oncogene homolog 1 (RAF1; HSA 3/MMU 6), and ceruloplasmin (CP; HSA 3/MMU 9). FIM3, SI, and CP mapped to bovine syntenic group U10, while RAF1 and GPX1 mapped to U12.