The Far Edge Of The Rice And Mushroom (zizania Latifiolia) Gradually Caused By Permeability Hybrid Rice Genome Wide Range Of Genetic Changes

Wide-hybridization plays an important role in plant speciation and evolution. Previous studies indicated that wide-hybridization can be accompanied by "programmed" sequence deletions . Our lab has succeed in crossing wild rice (.Zizania latifolid} with rice (cv. Matsumae),and produced progenies with extensive morphological changes. Previous studies showed that there were many sequencing changes in the genome of offspring introgression lines. In the present thesis I describe that I have detected genome-wide changes, at the DNA sequence level, with an unbias DNA fingerprinting method ~ the AFLP technology.We selected three representative introgression lines, and amplified a total of 3171 bands. The changed bands were detected in all three introgression lines. We got 1981 bands in RZ1 with 583 (29.4%) polymorphic bands; 2100 bands in RZ2 with 654 (31.1%) polymorphic bands; and 2098 bands in RZ35 with 686 (32.7%) polymorphic bands. The changes in DNA sequence were confirmed by Southern blot analysis. We cloned 466 bands to sequence. The sequencing results showed that the main mutation is base substitution, with occasional segment deletions and insertions. BlastX similarity search indicated that the non-coding sequences were 51.3%, the sequences encoding for putative proteins were 14.5%, and those encoding for known- function proteins were 13.6%. The rest sequences (20.6%) are recognizable transposons and retrotransposons. Taking advantages of the availability of the whole-genome rice sequence, we allocated all the sequenced fragments to the rice chromosomes, and found that there existed differences in terms of distribution of the changed fragments in the various introgression lines. Cluster analysis showed that all introgression lines have significantly diverged from each other and from their rice parental cultivar. The mean of changed fragments varied from 26.7 to 4.7. The difference also existed for a given chromosome of thethree introgression lines. T-test analysis implied that the sequence changes most probably occurred at the early stages of the "hybrid" embryo development, then being transmitted to the offsprings.