ISSN:
1573-6857
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The hybrid derivatives ofNicotiana tabacum (2n=48) (female parent) andN. plumbaginifolia (2n=20) carried a variable number ofN. plumbaginifolia (pbg) chromosomes inN. tabacum (tbc) nuclei. Onepbg chromosome carried a gene for chlorophyll (Ws, pbg) and thetbc genome was homozygous recessive for the white seedling lociws 1,ws 1,ws 2.ws 2. The hybrid derivatives showed chlorophyll variegation. Thepbg chromosome, carrying the geneWs (pbg) for chlorophyll production, also carried information for a particular intensity of variegation. The alien chromosome formed anaphase bridges in the somatic tissue and led to subsequent loss of chromatin material having theWs pbg gene, resulting in leaf-color variegation. The intensity of this variegation was determined by information contained in this same chromosome. Either a chromatid type of breakage-fusion-bridge cycle, or formation of independent mitotic bridges by allocyclic segments ofpbg chromosomes, followed by their unequal breakage and restitution of the broken ends, has been hypothesized to be the cause of loss of chromatin material and subsequently of chlorophyll variegation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02324462
