Development and chromosomal localization of genome-specific DNA markers of Brassica and the evolution of amphidiploids and n = 9 diploid species

Genome ◽  
1990 ◽  
Vol 33 (1) ◽  
pp. 131-142 ◽  
Author(s):  
K. Hosaka ◽  
S. F. Kianian ◽  
J. M. McGrath ◽  
C. F. Quiros

Ten genome-specific probes were developed from Brassica napus and B. oleracea genomic DNA libraries. Selection was based on polymorphism between and limited variation within genomes, permitting their localization on six individual C-genome chromosomes. Chromosome assignment was accomplished by using two sets of B. campestris – oleracea alien addition lines derived from (i) B. napus and (ii) the artificially synthesized B. napus 'Hakuran'. The presence of shared fragments between A, B, and C genomes indicates partial homology of the three genomes. However, several genome-specific markers could separate these three genomes. Genome-specific clones developed in this study served to confirm the parental diploid species originating the three amphidiploids, B. napus, B. carinata, and B. juncea. At least one clone suggests that B. napus has a polyphyletic origin. These clones were also useful to confirm the close evolutionary proximity among wild species in the B. oleracea cytodeme; however, no clear trends were found to suggest specific wild ancestors for the different B. oleracea horticultural types. Brassica oxyrrhina was distinct from other n = 9 species with most clones tested.Key words: restriction fragment length polymorphism, DNA marker, chromosome addition lines, Brassica oleracea cytodeme, amphidiploids, genome-specific markers.

Genome ◽  
2005 ◽  
Vol 48 (6) ◽  
pp. 959-970 ◽  
Author(s):  
I G Adonina ◽  
E A Salina ◽  
E G Pestsova ◽  
M S Röder

Overall, 253 genomic wheat (Triticum aestivum) microsatellite markers were studied for their transferability to the diploid species Aegilops speltoides, Aegilops longissima, and Aegilops searsii, representing the S genome. In total, 88% of all the analyzed primer pairs of markers derived from the B genome of hexaploid wheat amplified DNA fragments in the genomes of the studied species. The transferability of simple sequence repeat (SSR) markers of the T. aestivum A and D genomes totaled 74%. Triticum aestivum – Ae. speltoides, T. aestivum – Ae. longissima, and T. aestivum – Ae. searsii chromosome addition lines allowed us to determine the chromosomal localizations of 103 microsatellite markers in the Aegilops genomes. The majority of them were localized to homoeologous chromosomes in the genome of Aegilops. Several instances of nonhomoeologous localization of T. aestivum SSR markers in the Aegilops genome were considered to be either amplification of other loci or putative translocations. The results of microsatellite analysis were used to study phylogenetic relationships among the 3 species of the Sitopsis section (Ae. speltoides, Ae. longissima, and Ae. searsii) and T. aestivum. The dendrogram obtained generally reflects the current views on phylogenetic relationships among these species.Key words: Triticum aestivum, Aegilops speltoides, Aegilops longissima, Aegilops searsii, microsatellite, SSR, chromosome addition lines, phylogeny.


1968 ◽  
Vol 10 (3) ◽  
pp. 551-563 ◽  
Author(s):  
Hugh Thomas

Six of the possible seven single chromosome addition lines of the wild diploid species A. hirtula to the cultivated oat A. sativa have been identified. The effect of the single hirtula chromosome on the morphology of the recipient A. sativa variety Manod was variable depending on the chromosome involved and certain genes which are dominant at the diploid level were only partly expressed in the hexaploid background.The frequency with which the hirtula chromosomes paired with their equivalent chromosomes in A. sativa was less than that observed in primary trisomics, indicating that the hirtula As genome is only partly homologous with the A genome of the hexaploids. None of the disomic addition lines was sufficiently stable cytologically to maintain the line without the reversion of a proportion of the progeny to the monosomic condition and eventually to the euploid chromosome number of A. sativa.


Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 327-339 ◽  
Author(s):  
O Riera-Lizarazu ◽  
M I Vales ◽  
E V Ananiev ◽  
H W Rines ◽  
R L Phillips

Abstract In maize (Zea mays L., 2n = 2x = 20), map-based cloning and genome organization studies are often complicated because of the complexity of the genome. Maize chromosome addition lines of hexaploid cultivated oat (Avena sativa L., 2n = 6x = 42), where maize chromosomes can be individually manipulated, represent unique materials for maize genome analysis. Maize chromosome addition lines are particularly suitable for the dissection of a single maize chromosome using radiation because cultivated oat is an allohexaploid in which multiple copies of the oat basic genome provide buffering to chromosomal aberrations and other mutations. Irradiation (gamma rays at 30, 40, and 50 krad) of a monosomic maize chromosome 9 addition line produced maize chromosome 9 radiation hybrids (M9RHs)—oat lines possessing different fragments of maize chromosome 9 including intergenomic translocations and modified maize addition chromosomes with internal and terminal deletions. M9RHs with 1 to 10 radiation-induced breaks per chromosome were identified. We estimated that a panel of 100 informative M9RHs (with an average of 3 breaks per chromosome) would allow mapping at the 0.5- to 1.0-Mb level of resolution. Because mapping with maize chromosome addition lines and radiation hybrid derivatives involves assays for the presence or absence of a given marker, monomorphic markers can be quickly and efficiently mapped to a chromosome region. Radiation hybrid derivatives also represent sources of region-specific DNA for cloning of genes or DNA markers.


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