RESUMO
The goat CSN1S2 locus is characterized by the presence of three alleles, A, B and C, all associated with about 2.5 g/l of protein per allele. The SDS-PAGE analysis of 441 individual milk samples obtained from goats belonging to a population reared in Southern Italy showed that the milk produced by three goats did not apparently contain alpha s2-casein, whereas milk produced by 37 goats showed a less intense electrophoretic band of this casein fraction (about 50%). These results can be explained by hypothesizing the presence of another allele at this locus, CSN1S2o, associated with a 'null' content of alpha s2-casein. Southern blot, PCR and PCR-RFLP analyses of the DNA region containing the CSN1S2 gene of individuals producing milk with and without alpha s2-casein did not show differences between the two groups. As a consequence, goats producing milk without alpha s2-casein carry an apparently intact gene. The first results obtained by sequencing part of the CSN1S2o allele revealed a G-->A transition at nucleotide 80 of the 11th exon which creates a stop codon and could be responsible for the absence of the alpha s2-casein in goat milk. This mutation eliminates a NcoI restriction site. A test based on this polymorphism has been established in order to identify carriers of the CSN1S2o allele.
Assuntos
Alelos , Caseínas/genética , Cabras/genética , Fragmentos de Peptídeos/genética , Animais , Sequência de Bases , Southern Blotting , Caseínas/metabolismo , Códon de Terminação , DNA/genética , Primers do DNA , Eletroforese em Gel de Poliacrilamida , Fragmentos de Peptídeos/metabolismo , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de RestriçãoAssuntos
Caseínas/genética , Desoxirribonucleases de Sítio Específico do Tipo II/química , Cabras/genética , Polimorfismo de Fragmento de Restrição , Alelos , Animais , Caseínas/química , Primers do DNA/química , Frequência do Gene , Reação em Cadeia da Polimerase/veterinária , Mapeamento por Restrição/veterináriaAssuntos
Búfalos/genética , Bovinos/genética , Repetições de Dinucleotídeos/genética , Cabras/genética , Polimorfismo Genético/genética , Ovinos/genética , Animais , Mapeamento Cromossômico/veterinária , Primers do DNA , Frequência do Gene , Reação em Cadeia da Polimerase/veterinária , Valores de ReferênciaRESUMO
The bovine CSN1AG allele is associated with a lower proportion of alpha s1-casein in milk and is characterized by an insertion in the last noncoding exon (19th). According to DNA sequence analysis, the location, length, and origin of the insertion characterizing the bovine CSN1AG allele have been identified. This insertion interrupts the 19th exon between nucleotides 58 and 59, is 371 bp long, and has a high level of homology with relicts of long interspersed elements of retropositional origin. Northern blot analysis shows that the inserted element is transcribed and that the number of transcripts of the CSN1AG allele is less than one-half of the number of transcripts of the CSN1AB allele. The lower amount of alpha s1-casein in milk obtained from cows carrying the CSN1AG allele can be explained by a reduced mRNA stability. Furthermore, a method has been developed using polymerase chain reaction for identification of the carriers of the CSN1AG allele.
Assuntos
Caseínas/genética , Bovinos/genética , DNA/química , Alelos , Animais , Sequência de Bases , Northern Blotting , Éxons , Modelos Moleculares , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Reação em Cadeia da Polimerase , RNA Mensageiro/química , Sequências Repetitivas de Ácido Nucleico , Alinhamento de SequênciaAssuntos
Bovinos/genética , Repetições de Microssatélites , Polimorfismo Genético , Alelos , Animais , Sequência de Bases , Búfalos/genética , Mapeamento Cromossômico , Primers do DNA/genética , Repetições de Dinucleotídeos , Feminino , Frequência do Gene , Genes Dominantes , Ligação Genética , Masculino , Reação em Cadeia da PolimeraseRESUMO
In the sheep alpha alpha alpha globin gene haplotype, the three genes display from the 5' to the 3' end the percentage efficiencies of about 30:14:6, as indicated by the amounts of the three types of alpha chain produced in the alpha alpha alpha/alpha alpha alpha homozygotes. The 3' gene in the alpha alpha alpha alpha haplotype appears to have an efficiency around 1%, as suggested by analysis of one quadruple alpha homozygote. Moreover, the total outputs of the alpha alpha alpha as well as of the alpha alpha alpha alpha haplotypes do not substantially differ from that of the common alpha alpha haplotype.
Assuntos
Expressão Gênica , Globinas/genética , Família Multigênica , Animais , Globinas/biossíntese , Haplótipos , Focalização Isoelétrica , Polimorfismo de Fragmento de Restrição , OvinosRESUMO
By using seven endonucleases and four bovine cDNA probes specific for alpha S1-, alpha S2-, beta-, and kappa-casein genes, nine restriction fragment length polymorphisms (RFLPs) have been found in the sheep orthologous DNA regions. In contrast to the low level of variation observed at the protein level, these DNA polymorphisms determine a high level of heterozygosity and, therefore, represent useful tools for genetic analyses since they can also be obtained without the need for gene expression. In fact, informative matings suggest that in sheep, as in cattle, the four loci are linked.
Assuntos
Caseínas/genética , Polimorfismo Genético/genética , Ovinos/genética , Animais , Autorradiografia , Cruzamentos Genéticos , Sondas de DNA , Eletroforese em Gel de Poliacrilamida , Endonucleases , Feminino , Ligação Genética/genética , Marcadores Genéticos/genética , Variação Genética/genética , Heterozigoto , Masculino , Linhagem , Polimorfismo de Fragmento de RestriçãoRESUMO
DNA samples obtained from 8 goats, 1 moufflon, and 84 sheep with HbA, HbAB, and HbB belonging to different breeds were digested with BamHI, EcoRI, HindIII and PstI and probed with the 5' end of the goat epsilon IV- and psi beta Z-globin genes. Sheep homozygous for HbA show a different restriction pattern than sheep homozygous fo HbB with each of these endonucleases. The main difference is that HbB sheep lack the epsilon II and psi beta X genes. These results, in addition to those previously obtained using a probe specific for beta-globin genes, suggest that HbB sheep probably lack the preadult four-gene set. The DNAs from moufflon and sheep homozygous for HbA show indistinguishable restriction patterns. Furthermore, a number of restriction fragment length polymorphisms (RFLPs) are detected in the epsilon IV and psi beta Z DNA regions, and one HindIII RFLP in the epsilon VI DNA region.
Assuntos
Genes , Globinas/genética , Hemoglobina A/genética , Hemoglobinas/genética , Família Multigênica , Ovinos/genética , Animais , Artiodáctilos/genética , Embrião de Mamíferos , Cabras/genética , Mapeamento por Restrição , Especificidade da EspécieRESUMO
By using a bovine kappa-Cn cDNA as probe and the PstI endonuclease we demonstrate that the DNA restriction patterns of kappa-Cn AA and kappa-Cn BB cows are different. Besides two invariant fragments (about 6.8kb and 1.1kb) the former shows two fragments of about 4.3 kb and 0.3 kb and the latter one fragment of about 4.6 kb. kappa-Cn AB cows show intermediate pattern. Therefore, it is possible to determine the bovine kappa-Cn genotypes even in absence of gene product.
Assuntos
Caseínas/genética , Bovinos/genética , DNA/genética , Animais , Enzimas de Restrição do DNA , Feminino , Genótipo , Polimorfismo de Fragmento de RestriçãoRESUMO
By investigations at the DNA and protein level, it has been shown that in sheep a previously detected, presumed quantitative allele of the II alpha 113His gene, displaying a reduced efficiency (called the II alpha 113His decreases gene), is carried by a chromosome bearing three alpha-globin loci. In particular, five sheep having an alpha 113Leu/alpha 113His-chain ratio of about 13:1 (13:1 phenotype) possessed the -I alpha 113Leu-II alpha 113Leu-/-I alpha 113Leu-II alpha 113Leu-III alpha 113His decreases genotype. One sheep showing a alpha 113Leu/alpha 113His-chain ratio of about 3:1 (3:1 phenotype) had the -I alpha 113Leu-II alpha 113His-/-I alpha 113Leu-II alpha 113Leu-III alpha 113His decreases genotype, while one sheep having a chain ratio of about 6:1 (6:1 phenotype) carried the -I alpha 113Leu-II alpha 113Leu-II alpha 113His decreases-/-I alpha 113Leu-II alpha 113Leu-III alpha 113His decreases genotype. Nineteen sheep, displaying the common phenotypes, all possessed the alpha alpha/alpha alpha gene arrangement. Furthermore, the possible location of the gene with reduced efficiency and the expression of the three genes in the triple alpha-globin loci chromosome are discussed.
Assuntos
Globinas/genética , Família Multigênica , Ovinos/genética , Animais , DNA/análise , Histidina/genética , Focalização Isoelétrica , Leucina/genética , Fenótipo , Polimorfismo Genético , Ovinos/sangueRESUMO
DNA samples obtained from sheep homozygous for HbA, for HbB and heterozygous were subjected to Southern blot analysis using a goat beta F and a rabbit beta 1-globin gene as probes. Sheep homozygous for HbA show a different restriction pattern from that of sheep homozygous for HbB with each of the used endonucleases. The DNAs from moufflon and sheep homozygous for HbA show indistinguishable restriction patterns with some endonucleases. By means of double digestions it has been possible to construct restriction maps of the beta B and beta C genes and to confirm the absence of the beta C gene in HbB sheep.
