Molecular analysis of the structure of the maize B-chromosome.
The overall composition of the maize B is similar to that of the standard chromosome complement (A-chromosomes). This has been demonstrated by the use of several methods including: (a) genomic in situ hybridization (GISH), (b) analysis of highly repetitive sequences by the comparison of restriction digests of 0B and +B DNA and (c) the characterization of middle-repetitive cloned sequences. By the use of the technique of random amplification of polymorphic DNA-polymerase chain reaction, we have identified a B-specific repetitive sequence family. Sequence analysis of the B-specific clone reveals a relationship to the PREM-1 family of maize retroelements, which are preferentially transcribed in pollen. These results suggest an internal origin of the B-chromosome from within the maize genome, but demonstrate also that specific sequences can evolve by rapid processes of genomic turnover. Models for the origin of the maize B are discussed in the context of the present data.
Stark
E A
EA
Department of Botany, University of Reading, UK.
Connerton
I
I
Bennett
S T
ST
Barnes
S R
SR
Parker
J S
JS
Forster
J W
JW
D001483:Base Sequence; D015139:Blotting, Southern; D002875:Chromosomes / Q000737:chemistry*; D018745:Genome, Plant; D015698:Genomic Library; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D019105:Random Amplified Polymorphic DNA Technique; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D003313:Zea mays / Q000166:cytology / Q000235:genetics*