Mapping of rDNA on the chromosomes of Eleusine species by fluorescence in situ hybridization.

Abstract

Mapping of rDNA sites on the chromosomes of four diploid and two tetraploid species of Eleusine has provided valuable information on genome relationship between the species. Presence of 18S-5.8S-26S rDNA on the largest pair of the chromosomes, location of 5S rDNA at four sites on two pairs of chromosomes and presence of 18S-5.8S-26S and 5S rDNA at same location on one pair of chromosomes have clearly differentiated E. multiflora from rest of the species of Eleusine. The two tetraploid species, E. coracana and E. africana have the same number of 18S-5.8S-26S and 5S rDNA sites and located at similar position on the chromosomes. Diploid species, E. indica, E. floccifolia and E. tristachya have the same 18S-5.8S-26S sites and location on the chromosomes which also resembled with the two pairs of 18S-5.8S-26S rDNA locations in tetraploid species, E. coracana and E. africana. The 5S rDNA sites on chromosomes of E. indica and E. floccifolia were also comparable to the 5S rDNA sites of E. africana and E. coracana. The similarity of the rDNA sites and their location on chromosomes in the three diploid and two polyploid species also supports the view that genome donors to tetraploid species may be from these diploid species.

Genomic relationships among Nicotiana species with different ploidy levels revealed by 5S rDNA spacer sequences and FISH/GISH

“…Chromosomal localizations of rDNAs are helpful for inferring genome identity (Bisht and Mukai, 2000). However, data only by FISH are insufficient to evaluate the inter-genomic relationships in the putative amphidiploid Nicotiana species.…”

Chloroplast genes as genetic markers for inferring patterns of change, maternal ancestry and phylogenetic relationships among Eleusine species

“…Chromosome research has demonstrated the significant role of polyploidy and aneuploidy in the evolution of the genus (Chennaveeraiah and Hiremath 1974; Hiremath and Chennaveeraiah 1982; Hiremath and Salimath 1991; Bisht and Mukai 2000, 2001 a , b , 2002). Biochemical, nuclear and cpDNA markers have provided valuable insight into relationships, and on the origin of the crop species (Hilu et al 1978; Hilu 1988, 1995; Hilu and Johnson 1992, 1997; Werth et al 1993, 1994; Salimath et al 1995 a ; Neves et al 2005; Dida et al 2007, 2008; Liu et al 2011).…”

“…In spite of the enormous amount of information, there still exists considerable disagreement over the identification of the diploid ancestors of the three polyploid species and the level of speciation and evolutionary relationships among the nine species of Eleusine (Phillips 1972, 1995; Hilu and Johnson 1997; Lye 1999; Bisht and Mukai 2000, 2001 a , 2002; Devarumath et al 2005; Neves et al 2005; Liu et al 2011). Eleusine coracana (2 n = 4 x = 36) (AABB) is considered to be an allotetraploid and has been domesticated from its wild progenitor, Eleusine africana (2 n = 4 x = 36) (AABB) (Chennaveeraiah and Hiremath 1974; Hilu and deWet 1976; Hilu et al 1978; Hilu 1988, 1995; Hiremath and Salimath 1992; Werth et al 1994; Hilu and Johnson 1997; Bisht and Mukai 2000, 2001 a , b ; Devarumath et al 2005; Neves et al 2005; Dida et al 2007, 2008).…”

“…Eleusine coracana (2 n = 4 x = 36) (AABB) is considered to be an allotetraploid and has been domesticated from its wild progenitor, Eleusine africana (2 n = 4 x = 36) (AABB) (Chennaveeraiah and Hiremath 1974; Hilu and deWet 1976; Hilu et al 1978; Hilu 1988, 1995; Hiremath and Salimath 1992; Werth et al 1994; Hilu and Johnson 1997; Bisht and Mukai 2000, 2001 a , b ; Devarumath et al 2005; Neves et al 2005; Dida et al 2007, 2008). The genetic maps generated by Dida et al (2007) showed that E. coracana and E. africana are allotetraploids.…”

“…The genetic maps generated by Dida et al (2007) showed that E. coracana and E. africana are allotetraploids. There is also strong evidence to suggest that Eleusine indica (2 n = 2 x = 18) (AA) is the maternal genome donor of E. coracana and E. africana (Hilu 1988; Hiremath and Salimath 1992; Hilu and Johnson 1997; Bisht and Mukai 2000, 2001 a ; Neves et al 2005). Bisht and Mukai (2000, 2001 a , 2002) indicated that Eleusine floccifolia (2 n = 2 x = 18) could be the BB donor species of E. coracana .…”