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J B Dodgson

Publications and source records attributed to J B Dodgson.

66 records · Page 4Linked to original sources
PubMed1979

Isolation of the chicken beta-globin gene and a linked embryonic beta-like globin gene from a chicken DNA recombinant library.

A library of random chicken DNA fragments, 15-22 kb long, has been prepared in the vector lambda Charon 4A. This library was screened with combined adult and embryonic globin cDNA, and several independent globin gene-containing recombinants were isolated. One of these recombinants, lambda Chicken beta-globin 1 (lambda C beta G1), contains the adult chicken beta-globin gene and a closely linked embryonic beta-like globin gene. Both genes are transcribed in the same direction with the adult gene located 5' to the embryonic gene. Electron microscopic visualization of R loop structures generated by hybridization of globin RNA to lambda C beta G1 demonstrates that both globin genes contain major intervening sequences about 800 bp long, similar to those present in mammalian beta-globin genes. The adult beta-globin gene also contains a minor (approximately 100 bp long) intervening sequence analogous to the one observed in mammalian beta-globin genes. Restriction enzyme analysis of the adult beta-globin gene on lambda C beta G1 is consistent with the hypothesis that its two intervening sequences occur in the same positions with respect to the beta-globin amino acid sequence as do the corresponding mammalian intervening sequences.

Animals↗
PubMed1979

Gene localization by chromosome fractionation: globin genes are on at least two chromosomes and three estrogen-inducible genes are on three chromosomes.

Chicken metaphase chromosomes were partially purified by rate zonal centrifugation, and DNA was prepared from each of the fractions of the sucrose gradient. The DNA was digested with various restriction enzymes and subjected to electrophoresis in agarose gels. The DNA was transferred to nitrocellulose filters (as described by Southern), and the filters were hybridized with cDNA probes. Four globin genes alpha A, alpha D, beta, and rho or epsilon are located on at least two chromosomes, and three of the estrogen-inducible genes of the hen oviduct--ovalbumin, ovomucoid, and transferrin--are on three different chromosomes. These experiments also confirm our earlier assignment of the endogenous viral sequence related to Rous-associated virus-0 to a separate (and larger) chromosome than the cellular sequence related to the transforming gene of avian sarcoma virus (cellular sarc), although it now appears that cellular sarc is on a small macrochromosome, rather than on a microchromosome.

Animals↗
PubMed1978

Analysis of the adult and embryonic chicken globin genes in chromosomal DNA.

Globin-specific mRNA has been purified from the red blood cells of anemic adult hens and from those of 5-day and 7-day chick embryos. These RNA preparations were used to synthesize labeled cDNA for solution and filter hybridization (Southern blotting) experiments. Hybridization of cDNAs prepared with separated adult alpha- and beta-mRNAs and of rabbit globin-specific probes to restriction enzyme-digested, filter-bound chicken chromosomal DNA has shown that the adult globin genes of the chicken exist within EcoRI-cleaved chromosomal DNA fragments which are 4.3, 6.0, and 12.5 kilobase pairs (kbp) in size. These fragments contain the majority or entirety of the adult alpha D, beta, and alpha A genes, respectively. Furthermore, we present evidence that the predominant chicken embryonic globins are contained within EcoRI fragments 9.4 and 15 kbp in size. Evidence is also presented that the same globin organization exists in several different breeds of chickens and in several chicken culture cell types. Finally, it is demonstrated that the pattern of globin-specific hybridization to reticulocyte chromosomal DNA digested with several restriction enzymes is unchanged during erythropoietic development.

Animals↗
PubMed1977

Synthesis and thermal melting behavior of oligomer-polymer complexes containing defined lengths of mismatched dA-dG and dG-dG nucleotides.

Model DNA polymers containing heteroduplex regions of defined sequence and size were synthesized using polynucleotide phosphorylase and calf thymus terminal transferase. Heteroduplexes were of the form (dG)n-d(C12AmC-x), where m - 1-6, and (dG)n-d(C10GmC-x), where m = 1 and 3-5. Thermal melting studies of the model DNAs indicated that the heteroduplex regions did not disrupt the cooperative interaction between the flanking regions of dG-dC base pairs. thus, it is possible that the heteroduplex nucleotides are accommodated in a stacked helical structure.

DNA Nucleotidyltransferases↗
PubMed1977

Action of single-strand specific nucleases on model DNA heteroduplexes of defined size and sequence.

The sensitivity of the model DNAs containing dA-dG and dtg-dG heteroduplex regions of defined length to S1 and mung bean single-strand specific nucleases was tested by polyacrylamide gel electrophoretic analysis of the distribution of product oligonucleotides. Single-base mismatch heteroduplexes were extremely resistant to these nucleases, although low levels of cleavage at the heteroduplex nucleotide were observed at high nuclease concentrations. The nuclease sensitivity of dA-dtg heteroduplex regions increased gradually as the length of the heteroduplex region increased frome one to six nucleotides. The sensitivity of dG-dG heteroduplexes three to five nucleotides long was considerably greater than that of the single dtg-dG mismatch.

DNA, Single-Stranded↗
PubMed1975

Transmission of stability (telestability) in deoxyribonucleic acid. Physical and enzymatic studies on the duplex block polymer d(C15A15) - d(T15G15).

The properties of the duplex block polymer d(C15A15) - d(T15G15) were examined by thermal denaturation and nuclease susceptibility studies in the absence and presence of drugs (actinomycin and netropsin) which bind specifically to only one end of the block polymer. The nucleotide composition of one region of this synthetic double-helical DNA affected the properties of a contiguous but remote region. Furthermore, the binding of actinomycin influenced the properties of both the binding and nonbinding regions. These findings suggest a mechanism for gene regulation at a distance.

Adenosine Monophosphate↗
PubMedDate not supplied

Mapping DNA polymorphisms using PCR primers derived from the sequence of an avian CR1 element.

Primers complementary to the chicken middle repetitive sequence element CR1 were used to generate and simultaneously map polymorphic polymerase chain reaction products (CR1-PCR) with various chicken DNAs as templates. Ten primers were prepared using the sequence of a single CR1 element as a guide. These 10 primers generated 23 polymorphic CR1-PCR products. The average number of polymorphic CR1-PCR products generated using single primers (1.1 per primer) was significantly higher than the average number observed using combinations of two primers (0.3 per primer combination). The polymorphic CR1-PCR products were mapped in a subset of a reference backcross population designed for the genetic linkage analysis of the chicken. Nineteen of the polymorphic CR1-PCR products identified were assigned to 13 of 19 linkage groups characterized thus far in this population; three have yet to be linked to a specific map location. One of the CR1-PCR markers mapped to the chicken Z chromosome. There was no evidence for a significant clustering of CR1-PCR markers within the map, even at the site of the CR1 element whose sequence was used for primer design.

Animals↗
PubMedDate not supplied

An autosomal genetic linkage map of the chicken.

We have developed an autosomal genetic linkage map of the chicken genome using a subpanel of 52 DNAs from a previously described reference backcross mapping population. The population derived from a cross of an inbred Red Jungle Fowl male and a highly inbred White Leghorn female. The backcross subpanel used was made up of offspring of a single F1 male with four White Leghorn females. Ninety-eight markers consisting of classical and erythrocyte antigen genes, restriction fragment length polymorphisms, random amplified polymorphic DNA, and chicken CR1 repeat-element polymorphisms were typed. Seventy-two of these markers were resolved into 19 linkage groups. Four of the linkage groups were assigned to chromosomes 1, 4, and 17. Four linkage groups were associated with linkage groups published earlier. Linkages within approximately 27 cM can be detected with a lod score of 3 with the panel used. The preliminary map contains approximately 590 cM within the linkage groups, and approximately 70% of the randomly selected markers fell in one of the groups; however, a considerable portion of the genome may remain outside of the existing linkage groups. These markers greatly expand the existing linkage map of the chicken genome.

Animals↗