Quantitative DNA variation between and within chromosome complements of Vigna species (Fabaceae)

Abstract

Cytogenetical investigations, so far, on the organisation and evolution of the genomes of Vigna species have proved difficult due to small chromosome size, large chromosome number and uniformity in chromosome shape and size within and between the complements. In this investigation the nature and extent of DNA variation between thirteen diploid and one polyploid species have been estimated. The DNA variation between diploid species was small and species clustered around a mean value of 2.7 pg. The polyploid species had a greater DNA value of 4.95 pg. No significant variation in 2C DNA content was found between accessions of V. radiata. A comparison of the distribution of DNA among the chromosomes within complements has shown that the excess DNA acquired in evolution was distributed evenly in all chromosomes despite significant differences in chromosome size. The relative changes in chromatin area and DNA density which accompany evolutionary DNA variation was also compared.

Karyotype Analysis of Twelve Species belonging to Genus Vigna.

“…The chromosomal number 2n=22 for all the species , coincides with previous cytological report on other species of the same genus (Venora et al 1995), with the exception of V ambacensis that has been reported with 2n=20 (Dusseau and Magnaut 1941, Frahm-Leliveld 1965, Galasso et al 1996, Parida et al 1990), even Verdcourt (1970) reports 2n=20 both for V ambacensis and for other three species, between which V reticulata and V wittei that always resulted in 2n=22 under Table 3. Typical chromosome within each species (marker chromosome) the present study.…”

“…These values range theoretically from 0 to 100 for REC and Syi and from 0 to 50 for TF%, and therefore a karyotype with high values of these indices is considered low evolved. This evolution is also corroborated by cytophotometrical analysis: in fact DNA variation is small and species cluster around a mean value of 2.7 pg/4C nucleus (Parida et al 1990). No species, moreover, seems sufficiently close to V unguiculata the most karyologically evolved, to consent an easy flow of useful genes.…”

Genome sequencing of adzuki bean ( Vigna angularis ) provides insight into high starch and low fat accumulation and domestication

“…Additionally, adzuki bean can be used as a model species, especially for non-oilseed legumes because of its short growth period and small genome size (13,14).…”

Screening and Identification of SSR Markers for Genetic Diversity for Mungbean [Vigna radiata (L.) Wilczek]

“…radiata] is a grain legume originating from South Asia. It is a self-pollinated diploid species with a chromosome number of 2n = 22 with an estimated genome size of 543 mega bases (Mb) (Parida et al, 1990;Kang et al, 2014). The crop is originated in India and predominantly grown in China, India, Pakistan and Thailand (Karthikeyan et al, 2014).…”