Chromosome characterization and physical mapping of 18S rDNA in Lilium longiflorum originated interspecific hybrids using combined genomic and fluorescent in situ hybridization

Author(s):  
Md Mazharul Islam ◽  
Hyemin Lee ◽  
Deen Mohammad Deepo ◽  
Reshma Yesmin ◽  
Fahad Ramzan ◽  
...  

Abstract This study was aimed at differentiating parental genomes, examining intergenomic composition, and mapping mitotic metaphase chromosomes by localizing parental and 18S rDNA probes in seven interspecific hybrid progenies that originated from Lilium longiflorum. Since in situ hybridization has not been previously used in lily breeding, flow cytometry was used in conjunction with genomic and fluorescent in situ hybridization to determine the genomic contribution of each parent to the interspecific progenies. A significant variation was observed in the DNA content, chromosome length, and 18S loci in F1 as compared to the female and male parents. L. longiflorum showed nearly two times higher DNA content than the male parents and L. longiflorum × Asiatic progenies, but eight times higher than L. longiflorum × L. hansonii. Genomic in situ hybridization results revealed that both female and male parents contributed an equal number of chromosomes to their interspecific F1 offspring. Fluorescent in situ hybridization mapping revealed that 18S rDNA had 8, 6 and 7 loci in L. longiflorum parents, i.e., White heaven, Bright tower, and White tower, respectively, whereas each Asiatic cultivar and L. hansonii used as male showed 8 and 12 loci respectively. Interspecific progenies showed 8 and 7 loci in LA, and 10–11 in LM hybrids. These cytogenetic results implied equal genetic and chromosomal contribution from both parents to their intergenomic progenies. Therefore, this combined (Schwarzacher et al., 1992)cytogenetic method has the potential to be an affordable and time-saving approach in lily breeding that could determine the status of hybrids and their genomic origin while achieving physical mapping and detecting genes in different genomes.

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 274-281 ◽  
Author(s):  
Susan E Brown ◽  
Janice L Stephens ◽  
Nora LV Lapitan ◽  
Dennis L Knudson

Barley metaphase chromosomes (2n = 14) can be identified by fluorescence in situ hybridization (FISH) and digital imaging microscopy using heterologous 18S rDNA and 5S rDNA probe sequences. When these sequences are used together, FISH landmark signals were seen so that all 7 chromosomes were uniquely identified and unambiguously oriented. The chromosomal location of the landmark signals was determined by FISH to a barley trisomic series using the 18S and 5S probes labeled with different fluorophores. The utility of these FISH landmarks for barley physical mapping was also demonstrated when an Amy-2 cDNA clone and a BAC clone were hybridized with the FISH landmark probes.Key words: Hordeum vulgare, barley, FISH, 5S, 18S, rDNA, landmarks, chromosome.


Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 717-725 ◽  
Author(s):  
Jiming Jiang ◽  
Bikram S. Gill

Nonisotopic in situ hybridization (ISH) was introduced in plants in 1985. Since then the technique has been widely used in various areas of plant genome mapping. ISH has become a routine method for physical mapping of repetitive DNA sequences and multicopy gene families. ISH patterns on somatic metaphase chromosomes using tandemly repeated sequences provide excellent physical markers for chromosome identification. Detection of low or single copy sequences were also reported. Genomic in situ hybridization (GISH) was successfully used to analyze the chromosome structure and evolution of allopolyploid species. GISH also provides a powerful technique for monitoring chromatin introgession during interspecific hybridization. A sequential chromosome banding and ISH technique was developed. The sequential technique is very useful for more precise and efficient mapping as well as cytogenetic determination of genomic affinities of individual chromosomes in allopolyploid species. A critical review is made on the present resolution of the ISH technique and the future outlook of ISH research is discussed.Key words: in situ hybridization, physical mapping, genome mapping, molecular cytogenetics.


Author(s):  
David Sadílek ◽  
Jitka Vilímová ◽  
Tomáš Urfus

Abstract Genome size and the position of 18S ribosomal DNA (rDNA) were analysed in two Himacerus, eight Nabis and two Prostemma species from the family Nabidae using flow cytometry and fluorescence in situ hybrization techniques. The karyotypes of Nabis biformis and Nabis maoricus, each with 2n = 16 + XY, and Prostemma aeneicolle, with 2n = 26 + XY, were recorded for the first time. All the species displayed one or two 18S rDNA signals on the X chromosome and up to two signals on the Y chromosome. Several females exhibited two different types of X chromosome breakage, namely within or outside of the 18S rDNA region. Measurements of nuclear DNA content revealed significant differences between all three genera under study. Most notably, the nuclear DNA content of Himacerus species, with 2n = 32/36 + XY (2C = 9–10 pg), was double that of Nabis species, with 2n = 16 + XY (2C = 4–6 pg). Therefore, the previously rejected theory of an autosomal polyploidy event in the evolution of the genus Himacerus is strongly supported by the results of the present study and is now being resurrected.


Micron ◽  
2010 ◽  
Vol 41 (7) ◽  
pp. 729-734 ◽  
Author(s):  
Mara Cristina Almeida ◽  
Leonardo Gusso Goll ◽  
Roberto Ferreira Artoni ◽  
Viviane Nogaroto ◽  
Rodrigo Rodrigues Matiello ◽  
...  

Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 638
Author(s):  
Marcelo B. Medeiros ◽  
José F. M. Valls ◽  
Aluana G. Abreu ◽  
Gustavo Heiden ◽  
Suelma Ribeiro-Silva ◽  
...  

This study presents the status of ex situ and in situ conservation for the crop wild relatives of rice, potato, sweet potato, and finger millet in Brazil, and the subsequent germplasm collection expeditions. This research is part of a global initiative entitled “Adapting Agriculture to Climate Change: Collecting, Protecting, and Preparing Crop Wild Relatives” supported by the Global Crop Diversity Trust. Species of the primary, secondary, and tertiary gene pools with occurrences reported in Brazil were included: Oryza alta Swallen, O. grandiglumis (Döll) Prod., O. latifolia Desv., O. glumaepatula Steud., Eleusine tristachya (Lam.) Lam., E. indica (L.) Gaertn., Solanum commersonii Dunal, S. chacoense Bitter, Ipomoea grandifolia (Dammer) O’Donell, I. ramosissima (Poir.) Choisy, I. tiliacea (Willd.) Choisy, I. triloba L., and I. cynanchifolia Meisn. The status of the ex situ and in situ conservation of each taxon was assessed using the gap analysis methodology, and the results were used to plan 16 germplasm collection expeditions. Seeds of the collected material were evaluated for viability, and the protocols for seed germination and cryopreservation were tested. The final conservation score, resulting from the gap analysis and including the average of the ex situ and in situ scores, resulted in a classification of medium priority of conservation for all the species, with the exception of I. grandifolia (high priority). The total accessions collected (174) almost doubled the total accessions of these crop wild relatives incorporated in Embrapa’s ex situ conservation system prior to 2015. In addition, accessions for practically absent species were collected for the ex situ conservation system, such as Ipomoea species, Eleusine indica, and Solanum chacoense. The methods used for dormancy breaking and low temperature conservation for the Oryza, Eleusine, and Ipomoea species were promising for the incorporation of accessions in the respective gene banks. The results show the importance of efforts to collect and conserve ex situ crop wild relatives in Brazil based on previous gap analysis. The complementarity with the in situ strategy also appears to be very promising in the country.


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