Quantitative assessment of heteroplasmy levels in Senecio vulgaris chloroplast DNA.

Heteroplasmy in coding chloroplast DNA was only recently shown to occur and was so far not quantitatively assessed. We present a quantitative analysis of cpDNA heteroplasmy levels at a triazine-resistance determining site within and between individual Senecio vulgaris plants. Detectable levels of heteroplasmic haplotypes were observed in all tested plants. As expected, the levels of heteroplasmy vary greatly between plants. However, even within individual plants, the fraction of one haplotype may cover a range from below 1% to well over 90%. Our results suggest that heteroplasmy may be a common phenomenon in S. vulgaris. Possible consequences for molecular diagnostics of chloroplast encoded traits as well as evolutionary consequences of chloroplast heteroplasmy are discussed.