Variation in nuclear DNA content in Malus species and cultivated apples

Abstract

The nuclear DNA content for a group of 40 Malus species and hybrids has been estimated using flow cytometry. Estimates of nuclear DNA content for this germplasm collection range from 1.45 pg for Malus fusca (diploid) to 2.57 pg for Malus ioensis (triploid). Among diploids, the nuclear (2C) DNA ranges from 1.45 pg for M. fusca to 1.68 pg for Malus transitoria. Among triploids, the nuclear (3C) DNA content ranges from 2.37 pg / 3C for Malus sikkimensis to 2.57 pg / 3C for M. ioensis. Given the complexity of the apple genome and its suggested allopolyploid origin, the results obtained in this study confirm earlier reports that polyploids can easily withstand the loss of a certain amount of DNA, and that there is a slight tendency towards diminished haploid nuclear DNA content with increased polyploidy.

Genome Size Variation inMalusSpecies

“…The present data differed in average by 2% from the corresponding species analysed by Dickson et al [12]. A bigger difference exists to the data of Tatum et al [13] whereas variations in both directions occurred. Tatum et al [13] have already mentioned their differences to the former data of Dickson et al [12].…”

“…Nuclear DNA content represents an important biodiversity character with fundamental biological significance [17]. Studies on nuclear DNA content within Malus of the Rosaceae family were reported by Dickson et al [12] and Tatum et al [13]. The present study including 26 primary species and 20 species hybrids demonstrates the most comprehensive investigation of the genus Malus.…”

“…Dickson et al [12] used for the Malus experiments chicken erythrocytes nuclei that were previously fixed and stained, with a nuclear DNA content of 2.33 pg DNA per nucleus. Tatum et al [13] co-chopped experimental apple leaves together with maize (5.35 pg DNA per nucleus). The present data differed in average by 2% from the corresponding species analysed by Dickson et al [12].…”

“…Later, Dickson et al [12] reported on the DNA content for 17 Malus species and eight cultivated apples, together with other genera of Rosaceae. Tatum et al [13] determined the nuclear DNA content of various Malus species, hybrids, and cultivated apples included in the national core collection of Malus germplasm in the United States. The two main goals of this study were (1) to estimate the variation in the 2C nuclear DNA content for Malus species and of their species hybrids included in the Malus collection in the Institute for Breeding Research on Horticultural and Fruit Crops, Germany; (2) to inspect relationships between nuclear DNA content and geographical features of the taxa.…”

Multiple Models for Rosaceae Genomics

“…The apple genome, at 1.54 pg DNA/2C nucleus or 750 Mb per haploid genome complement, is approximately the same size as that of tomato (Solanum lycopersicum; Tatum et al, 2005). The apple molecular map currently has more than 900 markers on 17 linkage groups (Maliepaard et al, 1998;Liebhard et al, 2002Liebhard et al, , 2003aLiebhard et al, , 2003bXu and Korban, 2002b;Naik et al, 2006).…”