High-Resolution Physical Chromosome Mapping of Multigene Families in Lagria villosa (Tenebrionidae): Occurrence of Interspersed Ribosomal Genes in Coleoptera

2015 ◽  
Vol 146 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Leonardo Gusso Goll ◽  
Rodrigo R. Matiello ◽  
Roberto F. Artoni ◽  
Marcelo R. Vicari ◽  
Viviane Nogaroto ◽  
...  

The organization and mapping of multigene families can produce useful genetic markers, and its use may elucidate the mechanisms of karyotype variation and genomic organization in different groups of eukaryotes. To date, few species of Coleoptera have been analyzed using FISH for the location of multigene families. The purpose of this study was to use high-resolution chromosome mapping to establish the genomic organization of the 18S rDNA, 5S rDNA and histone H3 gene families in Lagria villosa. FISH was performed using 18S rDNA, 5S rDNA and histone H3 probes prepared via PCR labeling. Fiber-FISH for 18S and 5S rDNA indicated that both ribosomal elements are colocalized in the short arm of chromosome 4. Additionally, FISH, using the histone H3 probe, revealed that this sequence is found in only one autosomal pair and did not colocalize with rDNA. Fiber-FISH with 5S and 18S probes, used to improve the mapping resolution of these regions, showed that both genes are closely interspersed with varying amounts of both DNA classes.

Genome ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 167-172 ◽  
Author(s):  
Diovani Piscor ◽  
Patricia Pasquali Parise-Maltempi

The genus Astyanax is widely distributed from the southern United States to northern Patagonia, Argentina. While cytogenetic studies have been performed for this genus, little is known about the histone gene families. The aim of this study was to examine the chromosomal relationships among the different species of Astyanax. The chromosomal locations of the 5S rRNA and H3 histone genes were determined in A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, A. mexicanus (all 2n = 50), A. fasciatus (2n = 46), and A. schubarti (2n = 36). All eight species exhibited H3 histone clusters on two chromosome pairs. In six species (A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, and A. fasciatus), syntenic clusters of H3 histone and 5S rDNA were observed on metacentric (m) or submetacentric (sm) chromosomes. In seven species, clusters of 5S rDNA sequences were located on one or two chromosome pairs. In A. mexicanus, 5S rDNA clusters were located on four chromosome pairs. This study demonstrates that H3 histone clusters are conserved on two chromosome pairs in the genus Astyanax, and specific chromosomal features may contribute to the genomic organization of the H3 histone and 5S rRNA genes.


Genetics ◽  
1991 ◽  
Vol 128 (3) ◽  
pp. 595-606
Author(s):  
B L Hibner ◽  
W D Burke ◽  
T H Eickbush

Abstract The multigene families that encode the chorion (eggshell) of the silk moth, Bombyx mori, are closely linked on one chromosome. We report here the isolation and characterization of two segments, totaling 102 kb of genomic DNA, containing the genes expressed during the early period of choriogenesis. Most of these early genes can be divided into two multigene families, ErA and ErB, organized into five divergently transcribed ErA/ErB gene pairs. Nucleotide sequence identity in the major coding regions of the ErA genes was 96%, while nucleotide sequence identity for the ErB major coding regions was only 63%. Selection pressure on the encoded proteins cannot explain this difference in the level of sequence conservation between the ErA and ErB gene families, since when only fourfold redundant codon positions are considered, the divergence within the ErA genes is 8%, while the divergence within the ErB genes (corrected for multiple substitutions at the same site) is 110%. The high sequence identity of the ErA major exons can be explained by sequence exchange events similar to gene conversion localized to the major exon of the ErA genes. These gene conversions are correlated with the presence of clustered copies of the nucleotide sequence GGXGGX, encoding paired glycine residues. This sequence has previously been correlated with gradients of gene conversion that extend throughout the coding and noncoding regions of the High-cysteine (Hc) chorion genes of B. mori. We suggest that the difference in the extent of the conversion tracts in these gene families reflects a tendency for these recombination events to become localized over time to the protein encoding regions of the major exons.


Genome ◽  
2002 ◽  
Vol 45 (4) ◽  
pp. 661-669 ◽  
Author(s):  
Ali Masoudi-Nejad ◽  
Shuhei Nasuda ◽  
Akira Kawabe ◽  
Takashi R Endo

Gliadins are the most abundant component of the seed storage proteins in cereals and, in combination with glutenins, are important for the bread-making quality of wheat. They are divided into four subfamilies, the α-, β-, γ-, and ω-gliadins, depending on their electrophoresis pattern, chromosomal location, and DNA and protein structures. Using a PCR-based strategy we isolated and sequenced an ω-gliadin sequence. We also determined the chromosomal subarm location of this sequence using wheat aneuploids and deletion lines. The gene is 1858 bp long and contains a coding sequence 1248 bp in length. Like all other gliadin gene families characterized in cereals, the ω-gliadin gene described here had characteristic features including two repeated sequences 300 bp upstream of the start codon. At the DNA level, the gene had a high degree of similarity to the ω-secalin and C-hordein genes of rye and barley, but exhibited much less homology to the α- and β-gliadin gene families. In terms of the deduced amino acid sequence, this gene has about 80 and 70% similarity to the ω-secalin and C-hordein genes, respectively, and possesses all the features reported for other gliadin gene families. The ω-gliadin gene has about 30 repeats of the core consensus sequences PQQPX and XQQPQQX, twice as many as other gliadin gene families. Southern blotting and PCR analysis with aneuploid and deletion lines for the short arm of chromosome 1A showed that the ω-gliadin was located on the distal 25% of the short arm of chromosome 1A. By comparison of PCR and A-PAGE profiles for deletion stocks, its genomic location must be at a different locus from gli-A1a in 'Chinese Spring'.Key words: glutenin, omega gliadin, storage protein, Triticum aestivum, secalin.


2006 ◽  
Vol 29 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Lessandra Viviane de Rosa Santos ◽  
Fausto Foresti ◽  
Adriane Pinto Wasko ◽  
Claudio Oliveira ◽  
Cesar Martins

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