Identification of a precursor genomic segment that provided a sequence unique to glycophorin B and E genes

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.90.15.7220· OSTI ID:5957647

Onda, M; Kudo, S; Fukuda, M ^[1]; Rearden, A ^[2]; Mattei, G M ^[3]

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1. La Jolla Cancer Research Foundation, CA (United States)
2. Univ. of California, San Diego, La Jolla (United States)
3. Institut National de la Sante et de la Recherche Medicale, Marseilles (France)

Human glycophorin A, B, and E (GPA, GPB, and GPE) genes belong to a gene family located at the long arm of chromosome 4. These three genes are homologous from the 5'-flanking sequence to the Alu sequence, which is 1 kb downstream from the exon encoding the transmembrane domain. Analysis of the Alu sequence and flanking direct repeat sequences suggested that the GPA gene most closely resembles the ancestral gene, whereas the GPB and GPE gene arose by homologous recombination within the Alu sequence, acquiring 3' sequences from an unrelated precursor genomic segment. Here the authors describe the identification of this putative precursor genomic segment. A human genomic library was screened by using the sequence of the 3' region of the GPB gene as a probe. The genomic clones isolated were found to contain an Alu sequence that appeared to be involved in the recombination. Downstream from the Alu sequence, the nucleotide sequence of the precursor genomic segment is almost identical to that of the GPB or GPE gene. In contrast, the upstream sequence of the genomic segment differs entirely from that of the GPA, GPB, and GPE genes. Conservation of the direct repeats flanking the Alu sequence of the genomic segment strongly suggests that the sequence of this genomic segment has been maintained during evolution. This identified genomic segment was found to reside downstream from the GPA gene by both gene mapping and in situ chromosomal localization. The precursor genomic segment was also identified in the orangutan genome, which is known to lack GPB and GPE genes. These results indicate that one of the duplicated ancestral glycophorin genes acquired a unique 3' sequence by unequal crossing-over through its Alu sequence and the further downstream Alu sequence present in the duplicated gene. Further duplication and divergence of this gene yielded the GPB and GPE genes. 37 refs., 5 figs.

• OSTI ID: 5957647
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Vol. 90:15; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
HUMAN CHROMOSOMES
GENETIC MAPPING
MEMBRANE PROTEINS
BIOLOGICAL EVOLUTION
GENE RECOMBINATION
AMINO ACID SEQUENCE
APES
DNA SEQUENCING
GLYCOPROTEINS
ANIMALS
CHROMOSOMES
MAMMALS
MAPPING
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES
550400* - Genetics