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A Nave

Publications and source records attributed to A Nave.

11 recordsLinked to original sources
PubMed1997

A PCR-based test for the presence of endogenous virus gene evA in chickens.

An endogenous virus, denoted evA, is present at high frequency in all brown egg layer lines. Using inverse polymerase chain reaction (PCR) based on the viral LTR regions, products were obtained containing cellular sequences 5' and 3' to the viral insertion point. PCR of chicken genomic DNA was carried out, using primers chosen from the 5' and 3' cellular sequences and a primer chosen from either the U3 or U5 portions of the viral LTR. Amplification of DNA from birds that did not carry evA with the primer triplets always gave a single 364 bp reaction product, interpreted as representing the flank-to-flank amplification product. Amplification of DNA from known homozygous or heterozygous evA carriers, with the same primer triplets, always gave both the expected junction product and 364 bp product. Therefore, these primer sequences can be used to distinguish evA carriers from non-carriers but cannot distinguish between homozygous and heterozygous evA carriers.

Alpharetrovirus↗
PubMed1997

Minisatellite and microsatellite length variation at a complex bovine VNTR locus.

Length variation at the BTGL1 variable number of tandem repeat (VNTR) locus, which includes both minisatellite and microsatellite motifs, was examined in a wide sample of cattle. A total of 22 alleles were uncovered. The distribution of allele size variation implicated mechanisms involving both minisatellite and microsatellite sequences. This was confirmed by direct sequences of two alleles. Differences between the two alleles involved repeat number variation of microsatellite motifs and a complex event involving the minisatellite motif, but point mutations were not observed.

Animals↗
PubMed1994

How is it that microsatellites and random oligonucleotides uncover DNA fingerprint patterns?

Minisatellites, microsatellites, and short random oligonucleotides all uncover highly polymorphic DNA fingerprint patterns in Southern analysis of genomic DNA that has been digested with a restriction enzyme having a 4-bp specificity. The polymorphic nature of the fragments is attributed to tandem repeat number variation of embedded minisatellite sequences. This explains why DNA fingerprint fragments are uncovered by minisatellite probes, but does not explain how it is that they are also uncovered by microsatellite and random oligonucleotide probes. To clarify this phenomenon, we sequenced a large bovine genomic BamHI restriction fragment hybridizing to the Jeffreys 33.6 minisatellite probe and consisting of small and large Sau3A-resistant subfragments. The large Sau3A subfragment was found to have a complex architecture, consisting of two different minisatellites, flanked and separated by stretches of unique DNA. The three unique sequences were characterized by sequence simplicity, that is, a higher than chance occurrence of tandem or dispersed repetition of simple sequence motifs. This complex repetitive structure explains the absence of Sau3A restriction sites in the large Sau3A subfragment, yet provides this subfragment with the ability to hybridize to a variety of probe sequences. It is proposed that a large class of interspersed tracts sharing this complex yet simplified sequence structure is found in the genome. Each such tract would have a broad ability to hybridize to a variety of probes, yet would exhibit a dearth of restriction sites. For each restriction enzyme having 4-bp specificity, a subclass of such tracts, completely lacking the corresponding restriction sites, will be present. On digestion with the given restriction enzyme, each such tract would form a large fragment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Large restriction fragments containing poly-TG are highly polymorphic in a variety of vertebrates.

Southern blots of genomic DNA from a variety of species digested by restriction endonucleases having a four-bp specificity, were probed with a bovine genomic clone consisting of seven tandem poly-TG stretches separated by a 29bp linker sequence. Highly variable DNA 'fingerprint' patterns were obtained in chicken, sheep, and horse, moderately variable DNA 'fingerprints' in mouse and man, and a monomorphic pattern in Drosophila. In chicken, horse and man a (TG)10 synthetic oligonucleotide probe gave results identical to those given by the bovine probe. Furthermore, in chicken the DNA fingerprint variation showed typical Mendelian inheritance and differed from the fingerprints obtained with Jeffreys 33.6 and M13 minisatellite probes. Thus, for a variety of vertebrate species, poly-TG-containing probes can uncover useful genetic variation.

Animals↗
PubMed1990

(TG)n uncovers a sex-specific hybridization pattern in cattle.

Screening of a bovine genomic library with the human minisatellite 33.6 probe uncovered a family of clones that, when used to probe Southern blots of bovine genomic DNA digested with the restriction enzyme HaeIII or MboI, revealed sexually dimorphic, but otherwise virtually monomorphic, patterns among the larger DNA fragments to which they hybridized. Characterization of one of these clones revealed that it contains different minisatellite sequences. The sexual dimorphism hybridization pattern observed with this clone was found to be due to multiple copies of two tandemly interspersed repeats: the simple sequence (TG)n and a previously undescribed 29-bp sequence. Both repeats appear to share many genomic loci including autosomal loci. In contrast, Southern analysis of AluI- or HinfI-digested bovine DNA with the (TG)n repeat used as a probe yielded substantial polymorphism. These results show that (i) different minisatellites can be found in a cluster, (ii) both simple and more complex repeated sequences other than the simple quaternary (GATA)n repeat can be sexually dimorphic, and (iii) simple repeats can reveal substantial polymorphism.

Animals↗
PubMed1988

Screening of Israeli Holstein-Friesian cattle for restriction fragment length polymorphisms using homologous and heterologous deoxyribonucleic acid probes.

Genomic DNA of Israeli Holstein-Friesian dairy cattle were screened with a battery of 17 cloned or subcloned DNA probes in an attempt to document restriction fragment length polymorphisms at a number of genetic loci. Restriction fragment length polymorphisms were observed at the chymosin, oxytocin-neurophysin I, lutropin beta, keratin III, keratin VI, keratin VII, prolactin, and dihydrofolate reductase loci. Use of certain genomic DNA fragments as probes produced hybridization patterns indicative of satellite DNA at the respective loci. Means for distinguishing hybridizations to coding sequences for unique genes from those to satellite DNA were developed. Results of this study are discussed in terms of strategy for the systematic development of large numbers of bovine genomic polymorphisms.

Animals↗
PubMed1987

Restriction fragment length polymorphisms in dairy and beef cattle at the growth hormone and prolactin loci.

Two bovine populations, a Holstein-Friesian dairy stock and a synthetic (Baladi X Hereford X Simmental X Charolais) beef stock, were screened for restriction fragment length polymorphisms (RFLPs) at the growth hormone and prolactin genes. Most RFLPs at the growth hormone gene are apparently the consequence of an insertion/deletion event which was localized to a region downstream of the structural gene. The restriction map for the genomic region including the growth hormone gene was extended. Two HindIII RFLPs at the growth hormone locus, as well as several RFLPs at the prolactin gene, seemed to be the consequence of a series of point mutations. The results are discussed in terms of the possibility that minor genomic variability underlies quantitative genetic variation.

Animals↗
PubMed1986

Restriction fragment length polymorphism among Israeli Holstein-Friesian dairy bulls.

Israeli Holstein-Friesian dairy bulls were screened for restriction fragment length polymorphisms by hybridizing cloned DNA probes for bovine growth hormone, for chymosin, and for rat muscle beta-actin to restriction endonuclease-digested DNA immobilized on nitrocellulose filters. The population proved to be polymorphic at the growth hormone locus, with evidence consistent with the phenotypes being inherited in allelic fashion. A low level of polymorphism was also observed at one of the beta-actin gene family loci. The chymosin locus was monomorphic with the restriction enzymes utilized. The results illustrate the power of restriction fragment length polymorphism methodology in visualizing genetic variability in dairy cattle populations.

Actins↗