Cytogenetics

Establishment of the genomic in situ hybridization (GISH) technique for analysis in interspecific hybrids of Passiflora

C. A. F. Melo, Silva, G. S., and Souza, M. M., “Establishment of the genomic in situ hybridization (GISH) technique for analysis in interspecific hybrids of Passiflora”, vol. 14, pp. 2176-2188, 2015.

The genomic in situ hybridization (GISH) technique was applied to Passiflora interspecific F1 HD13-133 hybrids (Passiflora sublanceolata x Passiflora foetida) and HD15-101 (Passiflora gardineri x Passiflora gibertii), and the backcrossed hybrids (BC1) HD18-106 and HD18-113 (Passiflora sublanceolata x HD13-133).

Karyotype structure of Hypostomus cf. plecostomus (Linnaeus, 1758) from Tapajós River basin, Southern Amazon: occurrence of sex chromosomes (ZZ/ZW) and their evolutionary implications

L. C. Oliveira, Ribeiro, M. O., Dutra, E. S., Zawadzki, C. H., Portela-Castro, A. L. B., and Martins-Santos, I. C., “Karyotype structure of Hypostomus cf. plecostomus (Linnaeus, 1758) from Tapajós River basin, Southern Amazon: occurrence of sex chromosomes (ZZ/ZW) and their evolutionary implications”, vol. 14, pp. 6625-6634, 2015.

Hypostomus is a group of fish with numerical and struc­tural karyotypic variability. Among them, only six species, three of which belong to the Amazon basin, show a sex chromosome. In this study, we present the karyotype structure of Hypostomus cf. plecos­tomus from the Teles Pires river basin in the municipality of Alta Flo­resta, MT. The species has 2n = 68 and the karyotype formula 14m+ 24sm+ 14st+ 16a [fundamental number (FN) = 120] in males and 15m+ 24sm+14st+15a (FN = 121) in females and sex chromosomes ZZ/ZW.

Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum)

W. Nazeer, Ahmad, S., Mahmood, K., Tipu, A. L., Mahmood, A., and Zhou, B., “Introgression of genes for cotton leaf curl virus resistance and increased fiber strength from Gossypium stocksii into upland cotton (G. hirsutum)”, vol. 13, pp. 1133-1143, 2014.

Cotton leaf curl virus disease is a major hurdle for successful cotton production in Pakistan. There has been considerable economic loss due to this disease during the last decade. It would be desirable to have cotton varieties resistant to this disease. We explored the possibility of transferring virus resistant genes from the wild species Gossypium stocksii into MNH-786, a cultivar of G. hirsutum. Hybridization was done under field condition at the Cotton Research Station, Multan, during 2010-11. Boll shedding was controlled by application of exogenous hormones.

Polymorphisms of the nucleolus organizing regions in Loricaria cataphracta (Siluriformes, Loricariidae) of the upper Paraguay River basin indicate an association with transposable elements

F. E. Porto, Gindri, B. S., Vieira, M. M. R., Borin, L. A., Portela-Castro, A. L. B., and Martins-Santos, I. C., “Polymorphisms of the nucleolus organizing regions in Loricaria cataphracta (Siluriformes, Loricariidae) of the upper Paraguay River basin indicate an association with transposable elements”, vol. 13, pp. 1627-1634, 2014.

A cytogenetic analysis of Loricaria cataphracta revealed a diploid number of 2n = 64 chromosomes, distributed as 12 metacentric + 8 submetacentric + 2 subtelocentric + 42 acrocentric, with a fundamental number of 86. Analysis of the nucleolus organizing region (NOR) using silver nitrate impregnation and fluorescence in situ hybridization (18S rDNA probe) techniques showed intra-population chromosomal polymorphism that could be classified into five different patterns (I to V), involving four pairs of chromosomes (8, 9, 12, and 13).

Production and genetic characterization of interspecific hybrids among Crambe abyssinica, Crambe hispanica and Crambe kralikii

X. Z. Du, Huang, B. L., Guan, H., Li, Z. Y., and Huang, B. Q., “Production and genetic characterization of interspecific hybrids among Crambe abyssinica, Crambe hispanica and Crambe kralikii”, vol. 13, pp. 6995-7005, 2014.

In this paper, interspecific crosses among Crambe abyssinica, Crambe hispanica, and Crambe kralikii were reported. In the C. hispanica x C. abyssinica (H x A) cross, 118 F1 hybrids were produced without embryo rescue, while 5 F1 hybrids were obtained with embryo rescue, when C. hispanica was used as the female parent. In the reciprocal cross (A x H), 232 hybrids were obtained without embryo rescue. From more than 1000 C. kralikii flowers pollinated with pollen grains of C.

B chromosome prevalence and physical mapping of 18S rDNA and H4 histone sites in the grasshopper Xyleus discoideus angulatus (Romaleidae)

C. B. Machado, Neto, L. C. Silva, Loreto, V., and Souza, M. J., “B chromosome prevalence and physical mapping of 18S rDNA and H4 histone sites in the grasshopper Xyleus discoideus angulatus (Romaleidae)”, vol. 13, pp. 7052-7060, 2014.

We sampled 11 natural populations of the grasshopper Xyleus discoideus angulatus in Northeastern Brazil to analyze B chromosome frequency and meiotic behavior. We observed a single large B chromosome, resembling the X chromosome, in 29 of the 402 specimens. Eight of the 11 populations had B chromosomes, with a rather broad geographical distribution, suggesting that this is an ancient polymorphism; significant differences were observed in B chromosome prevalence among the populations. Presence of the B chromosome was associated with increased frequency of macrospermatids.

Distribution of constitutive heterochromatin in Triatoma melanocephala (Hemiptera, Triatominae)

K. C. C. Alevi, Rosa, J. A., and Azeredo-Oliveira, M. T. V., “Distribution of constitutive heterochromatin in Triatoma melanocephala (Hemiptera, Triatominae)”, vol. 13, pp. 7899-7903, 2014.

In principle, Triatoma melanocephala was included in the Brasiliensis subcomplex on the basis of morphological parameters and geographical layout, since there were no other relevant data available in the literature. On the basis of karyotype, it has been proposed to exclude T. melanocephala, as well as of T. vitticeps and T. tibiamaculata, from the subcomplex, which shows fragmentation of the X sex chromosomes, thereby approaching the species of North America.

Karyomorphology and karyotype asymmetry in the South American Caesalpinia species (Leguminosae and Caesalpinioideae)

P. S. Rodrigues, Souza, M. M., and Corrêa, R. X., “Karyomorphology and karyotype asymmetry in the South American Caesalpinia species (Leguminosae and Caesalpinioideae)”, vol. 13, pp. 8278-8293, 2014.

With the purpose of addressing the pattern of karyotype evolution in Caesalpinia species, chromosome morphology was characterized in five species from Brazil, and karyotypic asymmetry was analyzed in 14 species from South America. All accessions had the chromosome number 2n = 24, which was first described here for Caesalpinia laxiflora Tul. and Cenostigma macrophyllum Tul. The karyotype formula of C. laxiflora, Caesalpinia pyramidalis Tul., and C. macrophyllum was 12 m.

Is there a relationship between polyploidy and stressful environments? A case study of inselbergs in northeastern Brazil

S. R. Pitrez, Andrade, L. A., Assis, F. N. M., and Felix, L. P., “Is there a relationship between polyploidy and stressful environments? A case study of inselbergs in northeastern Brazil”, vol. 13, pp. 8353-8366, 2014.

The aim of this study was to examine the hypothesis that plants with higher ploidy levels are selected by environments under more extremely stressful conditions than the same (or closely related) species from less rigorous terrestrial or epiphytic habitats. Therefore, we analyzed the chromosome numbers of 26 species belonging to 21 genera and 13 families of angiosperms that were collected on 4 inselbergs in Paraiba State, northeastern Brazil.

Population divergence and peculiar karyoevolutionary trends in the loricariid fish Hypostomus aff. unae from northeastern Brazil

J. A. Bitencourt, Affonso, P. R. A. M., Giuliano-Caetano, L., Carneiro, P. L. S., and Dias, A. L., “Population divergence and peculiar karyoevolutionary trends in the loricariid fish Hypostomus aff. unae from northeastern Brazil”, vol. 11, pp. 933-943, 2012.

Loricariidae (Siluriformes, Hypostominae) is one of the most diverse catfish families. In spite of the wide distribution of loricariids in South America, cytogenetic reports are available for only a few species, mostly from southern and southeastern Brazil. We made the first chromosomal analysis of Hypostomus aff. unae from the Contas River basin in northeastern Brazil.

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