Oat–maize chromosome addition lines: A new system for mapping the maize genome

Abstract

Novel plants with individual maize chromosomes added to a complete oat genome have been recovered via embryo rescue from oat (Avena sativa L., 2n ‫؍‬ 6x ‫؍‬ 42) ؋ maize (Zea mays L., 2n ‫؍‬ 20) crosses. An oat-maize disomic addition line possessing 21 pairs of oat chromosomes and one maize chromosome 9 pair was used to construct a cosmid library. A multiprobe (mixture of labeled fragments used as a probe) of highly repetitive maize-specific sequences was used to selectively isolate cosmid clones containing maize genomic DNA. Hybridization of individual maize cosmid clones or their subcloned fragments to maize and oat genomic DNA revealed that most high, middle, or low copy number DNA sequences are maize-specific. Such DNA markers allow the identification of maize genomic DNA in an oat genomic background. Chimeric cosmid clones were not found; apparently, significant exchanges of genetic material had not occurred between the maize-addition chromosome and the oat genome in these novel plants or in the cloning process. About 95% of clones selected at random from a maize genomic cosmid library could be detected by the multiprobe. The ability to selectively detect maize sequences in an oat background enables us to consider oat as a host for the cloning of specific maize chromosomes or maize chromosome segments. Introgressing maize chromosome segments into the oat genome via irradiation should allow the construction of a library of overlapping fragments for each maize chromosome to be used for developing a physical map of the maize genome.

Long-range patterns of diversity and linkage disequilibrium surrounding the maize Y1 gene are indicative of an asymmetric selective sweep

“…1) and the BAC end sequences from all of the BACs within the contig. The low copy nature of each was confirmed by chromosome 6-specific PCR amplification from a complete set of maize-oat addition lines (13). Shotgun sequencing of the Y1-containing BAC identified a homolog of the barley MLO gene (20) Ϸ1 kb from the most common Y1 transcription stop site.…”

“…To confirm chromosome 6 location of the amplicons, PCR was first performed on the 10 maize oat addition lines (13) as well as on a positive maize control and a negative oat control by using the conditions described (8) and 20 ng of DNA. If PCR product was present in the negative oat control reaction, then the PCR was reoptimized on Mo17 maize DNA using a gradient thermocycler (Eppendorf).…”

High-Resolution Radiation Hybrid Map of Wheat Chromosome 1D

“…The first plant RH panel was constructed by irradiating maize chromosome 9 in an oat background (oatmaize addition lines) with 30-, 40-, and 50-krad g-rays and subsequent characterization of these lines with maize-specific molecular markers (Riera-Lizarazu et al 1996Ananiev et al 1997). Using a combination of maize-specific probes, the average maize marker retention frequency was estimated to be 85, 83, and 75% for the 30-, 40-, and 50-krad treatments, respectively.…”

Radiation Hybrid Mapping of the Species Cytoplasm-Specific (scsae) Gene in Wheat

“…This potential has been realstanding and manipulation of this process in crop improvement. The objectives of this study were (1) to ized in maize for mapping duplicated sequences, gene families, and molecular markers to chromosome segexplore the influence of radiation on chromosome breakage in wheat and (2) to localize the scs ae gene using ments and for functional genomics analyses using oatmaize chromosome addition lines (Ananiev et al 1997; RH mapping methodology. Riera- Lizarazu et al 2000;Kynast et al 2002).…”