Analysis of the mitochondrial genome of Larix.

Abstract

We have isolated both mitochondrial and total genomic DNA from Larix species to examine the physical and genetic complexity of mitochondrial DNA and to determine mitochondrial inheritance patterns in Larix hybrid crosses, using restriction endonuclease and Southern hybridization analyses with specific wheat mitochondrial gene probes. In addition, these techniques have been used to identify restriction fragment length polymorphisms in somatic embryogenic cell cultures and corresponding regenerated hybrid Larix trees. Evaluation of mitochondrial gene hybridization patterns of two Larix species and their reciprocal hybrids demonstrated a maternal mode of inheritance of mitochondrial DNA gene sequences. Conifers appear to have evolved mechanisms for organelle exclusion during fertilization, resulting in a predominantly uniparental mode of inheritance of their organelles (Owens and Morris, 1990). Maternal inheritance of the mitochondrial genome together with paternal inheritance of the chloroplast genome in Larix hybrid crosses will be useful in the determination of maternal and paternal contributions in hybrid and introgressed Larix populations, and will increase the precision in determining phylogenies of this species. (Abstract shortened by UMI.)