Quantitative Evaluation by Reassociation Kinetics of Agrobacterium DNA Sequences residing in the Genome of a Crown-gall Tissue 2

The amount of homologous Agrobacterium tumefaciens DNA carriedin the genome of Scorzonera hispanica Crown-gall tissue cultureshas been determined from the reassociation kinetics of ³²P-labelledbacterial DNA in the presence of unlabelled Crown-gall DNA.Unrepeated DNA extracted from Crown-gall tissues was found tocontain sequences homologous to the bacterial DNA; quantitativeestimation shows the equivalent of about one Agrobacterium genomeper copy of unrepeated Crown-gall DNA. It is concluded thatan entire single genome of Agrobacterium is integrated intoeach haploid complement of a Crown-gall cell.     

Repetitive DNA of Higher Plants: SEPARATION OF FRACTIONS OF DIFFERENT COMPLEXITY FROM JERUSALEM ARTICHOKE TISSUES BY REASSOCIATION KINETICS

Jerusalem artichoke DNA, extracted from resting rhizomes, wasanalysed by the reassociation kinetics of sheared denaturedfragments. Various fractions were isolated according to theirreassociation rates. The slowest fractions consist of unrepeatedor single-copy DNA which makes up 55 per cent of the total DNA.The total sequence length of the haploid genome is estimatedas corresponding to 0.23?10¹² daltons. Among the fractions ofrepeated DNA isolated, two were relatively homogeneous withan average complexity of 2?10⁸ and 10⁹ daltons respectively.