Showing papers by "Richard A. Flavell published in 1979"

Structure of the human fetal globin gene locus

Abstract: We have derived a 'map' of restriction enzyme sites in and around the human gamma-globin genes. This has enabled us to show that there are two gamma-globin genes per haploid set, that the genes contain 'introns' within the same regions of DNA as the human beta and delta-globin genes, and that the genes are 3,500 base pairs apart. We conclude that the correct gene organisation of the human beta-like globin locus is GgammaAgammadeltabeta.

The structure of the human β-globin gene in β-thalassaemia

Abstract: Twenty-one cases of beta 0 and beta +-thalassaemia have been analysed by restriction endonuclease mapping. In most cases no deletion in the regions surrounding the beta- and delta-globin genes could be detected. However, in a single Asian case of beta 0-thalassaemia, homozygous clinically, one of the homologous chromosomes contained a beta-globin gene with a deletion of 600 base pairs of DNA and comprising most or all of the 3' end of the structural gene including the EcoRI restriction site within the beta-globin coding sequence.

Repeated sequence DNA comparisons between Triticum and Aegilops species

Abstract: The families of repeated sequences in the genomes of a range of Triticum and Aegilops species have been compared. All the genomes are very similar. However, using a DNA probe from Aegilops speltoides that contains the most highly repeated sequences, diploid Aegilops species could be distinguished from diploid Triticum species. Different Aegilops species' DNAs also hybridise to differing extents with this probe. The results are consistent with the hypothesis that speciation is accompanied by quantitative changes in the repeated sequence complements of genomes. Most if not all of the families of repeated sequences in hexaploid wheat can be detected in Aegilops speltoides (related to the B genome) and in Aegilops squarrosa (related to the D genome). However, some families of repeated sequences of hexaploid wheat were not found in Triticum monococcum (related to the A genome). Some of the most highly repeated sequences of hexaploid wheat are preferentially concentrated in the B genome. These sequences are useful as probes for distinguishing the three diploid genomes of hexaploid wheat.

Structure of the human G gamma-A gamma-delta-beta-globin gene locus

Abstract: We have constructed a physical map of the human G gamma-, A gamma-, delta-, and beta-globin genes. The previously described maps of the fetal and adult beta-like globin genes have been linked to one another by identification of a DNA fragment, generated by BamHI, that contains part of each of the A gamma- and delta-globin genes. The map obtained, which spans more than 40 kilobases, shows the following intergene distances: between G gamma and A gamma, 3500 base pairs; between A gamma and delta, 13,500 base pairs; and between delta and beta, 5500 base pairs. All genes are transcribed from the same DNA strand.

The structure and expression of globin genes in rabbit and man

Abstract: The rabbit and human β-related globin genes have been analysed using genomic 'Southern blotting' and molecular cloning. The rabbit β-globin gene structure has been worked out in detail and its transcripts have been characterized by S₁ nuclease transcription mapping. The arrangement of the human γδβ-globin gene locus has been largely elucidated. The gene order is (5' to 3') GγAγδβ and the intergene distances are Gγ-Aγ, 3.5 kb; Aγ-δ, 13.5 kb; δ-β, about 6 kb. All these β-related globin genes are transcribed from the same DNA strand. Several abnormal globin genes have been characterized by the same methods. Thus, δβ°-thalassaemia is the result of a deletion which begins approximately in the δ-globin gene large intron and extends beyond the β-globin gene. A form of β°-thalassaemia has been mapped where a 600 by deletion, including the 3' exon of the β-globin gene, has occurred.

The structure and expression of normal and abnormal globin genes

Abstract: Publisher Summary This chapter focuses on the structure and expression of normal and abnormal globin genes. Most mammalian genes are present as a single copy per haploid genome and, hence, comprise only about one part in 106 of the total nuclear DNA. This fact impeded work on single-copy genes, but recently recombinant DNA technology and sensitive gene mapping has led to the elucidation of the structure of a number of eukaryotic genes. The chapter examines the structure of the rabbit β-globin gene. The initial approach was to construct a detailed physical map of the rabbit β-globin gene using the blotting-filter hybridization approach. This showed that the β-globin gene consists of at least two noncontiguous blocks of coding sequences separated by an intervening sequence (IVS) of 600 base pairs (bp). The experiments showed that two intervening sequences are present in the rabbit β-globin gene, one of 126 bp in length in length present between the DNA sequences for amino acid 30 and 31 and the one already mentioned above of 573 bp long, present between the sequences coding for amino acids 104 and 105.

THE STRUCTURE OF CLONED RABBIT AND MOUSE β-GLOBIN GENES

Abstract: Cloned β-globin genes of both mouse and rabbit each contain a large and a small intervening sequence (intron) of about equal length at precisely the same positions relative to the coding sequence. The homologous introns show some sequence similarity, particularly at the junctions with the coding sequence. They most likely arose from a common ancestral sequence and diverged substantially during evolution.