Nuclear DNA content determination in Characiformes fish (Teleostei, Ostariophysi) from the Neotropical region

Margarida Lima Carvalho,Claudio Oliveira,Maria Clara Navarrete,Fausto Foresti,Otávio Froehlich

doi:10.1590/s1415-47572002000100010

Abstract

In the present study, nuclear DNA content was analyzed in 53 species of Characiformes fish from the Neotropical region. Diploid number ranged from 2n = 48 in Astyanax fasciatus, Gymnocorymbus ternetzi and Hyphessobrycon griemi to 2n = 102 in Potamorhina squamoralevis, with a modal number of 54 chromosomes. Nuclear DNA content ranged from 1.70 ± 0.04 pg of DNA per diploid nucleus in Acestrorhynchus pantaneiro to 3.94 ± 0.09 pg in Tetragonopterus chalceus. A general analysis showed a mean value of 2.9 pg of DNA per diploid nucleus. Very similar DNA content values were observed in the species of the family Cynodontidae which showed a variation of 3% between the two genera studied. Small variations were observed between populations of Gymnocorymbus ternetzi, Astyanax fasciatus and Moenkhausia sanctaefilomenae (Characidae, Tetragonopterinae). The subfamilies Tetragonopterinae and Acestrorhynchinae (Characidae) presented the widest range, about 96%. Even in those families in which diploid number and karyotypic formulae were conserved such as the families Anostomidae, Curimatidae, and Prochilodontidae, episodes leading to losses or gains of genetic material became fixed in their evolutionary history.

Highlights

IntroductionStudies of nuclear DNA content in living organisms in general and in fish in particular have been conducted using Feulgen-stained blood smears and microdensitometry analysis (Hinegardner and Rosen, 1972; Gold and Price, 1985; Majumdar and McAndrew, 1986; Gold and Amemiya, 1987; Oliveira et al, 1992, 1993a and 1993b; Carvalho et al, 1998), or blood cell samples in suspension, stained with base-specific fluorochromes and analyzed by flow cytometry (Thorgaard et al, 1982; Johnson et al, 1987; Tiersch and Chandler, 1989; Tiersch et al, 1989a, 1989b and 1990).Among vertebrates, DNA content has been observed to range from 0.78 to 280.00 pg per diploid nucleus (Olmo et al, 1989)
DNA content ranges from 0.78 pg per diploid nucleus in Tetraodon fluviatis (Hinegardner and Rosen, 1972) to 248.00 pg in Lepidosiren paradoxa
The analysis of nuclear DNA content poses a problem for evolutionary genetics regarding the interpretation of this quantitative variation in genome size or in DNA amount (Gold and Price, 1985)

Summary

Introduction

Studies of nuclear DNA content in living organisms in general and in fish in particular have been conducted using Feulgen-stained blood smears and microdensitometry analysis (Hinegardner and Rosen, 1972; Gold and Price, 1985; Majumdar and McAndrew, 1986; Gold and Amemiya, 1987; Oliveira et al, 1992, 1993a and 1993b; Carvalho et al, 1998), or blood cell samples in suspension, stained with base-specific fluorochromes and analyzed by flow cytometry (Thorgaard et al, 1982; Johnson et al, 1987; Tiersch and Chandler, 1989; Tiersch et al, 1989a, 1989b and 1990).Among vertebrates, DNA content has been observed to range from 0.78 to 280.00 pg per diploid nucleus (Olmo et al, 1989). Studies of nuclear DNA content in living organisms in general and in fish in particular have been conducted using Feulgen-stained blood smears and microdensitometry analysis (Hinegardner and Rosen, 1972; Gold and Price, 1985; Majumdar and McAndrew, 1986; Gold and Amemiya, 1987; Oliveira et al, 1992, 1993a and 1993b; Carvalho et al, 1998), or blood cell samples in suspension, stained with base-specific fluorochromes and analyzed by flow cytometry (Thorgaard et al, 1982; Johnson et al, 1987; Tiersch and Chandler, 1989; Tiersch et al, 1989a, 1989b and 1990). DNA content ranges from 0.78 pg per diploid nucleus in Tetraodon fluviatis (Hinegardner and Rosen, 1972) to 248.00 pg in Lepidosiren paradoxa (Ohno and Atkin, 1966). The analysis of nuclear DNA content poses a problem for evolutionary genetics regarding the interpretation of this quantitative variation in genome size or in DNA amount (Gold and Price, 1985)

Objectives

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Results