主题：【资料】叶绿体基因组课件

Table 1. Genes encoded by the Atropa belladonna plastid genome

Table 2. Comparison of the number of plastid genes in selected functional groups among photosynthetic organisms

List of intron containing genes in the coffee ct.genome

Endosymbiotic theory
n first proposed by Lynn Margulis (a former Boston Univ.
Biologist) in 1960’s
n mitochondria: the result of endocytosis of
α-proteobacteria (aerobic bacteria)
n chloroplasts: endocytosis of cyanobacteria
n mt & cp : bound by two membranes; involved in
energy metabolisms

Origin of Eukaryotic Diversity

Gene transfer from the cp to nucleus

has occurred over evolutionary time and is　an ongoing process.

Plastid to Nucleus Gene Transfer
• Cyanobacteria as endosymbiont 1.2 Billon years
• Plastids import 3000-5000 proteins
• Arabidopsis Nuclear genome has 4500 genes of
cyanobacterial origin
• At least 50% of this targeted to chloroplasts
• rpl22, infA moved to the nucleus 100 million years ago
• Transferred genes must first express in the nuclear
genome, acquire eukaryotic promoters, should be
translated on cytosolic ribosomes
• Acquire targeting sequences to return protein back to
chloroplasts
• These events should take several million years


Plastid to Mitochondria Gene
Transfer
• Observed only in higher plants, absent in
mosses & algae
• Entire chloroplast genome is present in
mitochondrial genome, transferred as
small or large fragments
• Chloroplast tRNAS are functional in
mitochondria
• Chloroplast regulatory sequences are
functional in mitochondria