Chloroplast DNA variation and parentage analysis in 55 apples.

Area of Science:

• Genetics
• Plant Biology
• Molecular Evolution

Background:

• Understanding apple (Malus x domestica) genetic diversity is crucial for breeding and conservation.
• Chloroplast DNA (cpDNA) is maternally inherited and useful for tracing lineage.

Purpose of the Study:

• To sequence a specific chloroplast DNA region (atpB-rbcL spacer and partial rbcL) in various apple cultivars and wild species.
• To assess the genetic variation within this cpDNA region.
• To propose parentage and infer wild origins for apple varieties based on cpDNA data.

Main Methods:

• DNA sequencing of the atpB-rbcL spacer and the first 53 codons of the rbcL gene.
• Analysis of 904 base pair sequences from 40 apple cultivars and 15 wild species.
• Identification of mutation sites within the sequenced cpDNA region.

Main Results:

• Low genetic variation was observed, with only five mutation sites identified across all samples.
• Maternal inheritance patterns of cpDNA allowed for the proposal of parentage for several apple cultivars.
• Putative wild origins were suggested for Malus x domestica.

Conclusions:

• The sequenced chloroplast DNA region exhibits limited variability in apples.
• cpDNA analysis provides insights into apple cultivar parentage and evolutionary origins.
• Further investigation may be needed to fully elucidate complex parentage and wild relationships.