1 The first endiosymbiosis ended in a great diversification of
2 a lineage comprising \textit{Red Algae, Green Algae} and \textit{Land Plants} (terrestrial).
3 Several Second Enbiosymbioses occurred then: two involving a Red
4 Algae and other heterotrophic eucaryotes and giving birth to both Brown
5 Algae and Dinoflagellates lineages; another involving a Green Algae and
6 a heterotrophic eucaryot and giving birth to Euglens.\\
7 The interesting with the tree produced (especially from DOGMA) is
8 that organisms resulting from the first endosymbiosis are distributed in
9 every of the lineage found in the chloroplast genome structure
10 evolution: with Red Algae chloroplasts together in one lineage, and
11 Green Algae and Land Plants chloroplasts together in antoher lineage;
12 while oranisms resulting from secondary endosymbioses are localized in
13 the tree: both the chloroplasts of Brown Algae and Dinoflagellates
14 representatives are found exclusively in the lineage also comprising the
15 Red Algae chloroplasts from which they evolved, while the Euglens
16 chloroplasts are related to the Green Algae chloroplasts from which they
17 evolved. This make sense in term of biology and history of lineages and
18 theories of chloroplasts (and so photosynthetic ability) origins in
19 different Eucaryotic lineages.
20 Interestingly, The sole organisms included that possesses a
21 chloroplast (and so a chloroplastic genome) but that have lost the
22 photosynthetic ability (being parasitic plants) are found at the base of
23 the tree, and not together with its related species phylogenetically,
24 meaning that functional chloroplast genes are evolutionnary constrained
25 when used in photosynthetic process, but loose rapidly their efficiency
26 when not used. They are Cuscuta-grovonii an Angiosperm (flowering plant)
27 at the base of the DOGMA Angiosperm-Conifers branch, and
28 Epipactis-virginiana also an Angiosperm at the complete base of the tree.
29 Another interesting result is that land plants that
30 represent single sublineage originating from the large and diverse
31 lineage of green algae in Eucaryots history are present in two different
32 branches of the DOGMA tree, associated with Green Algae, one branch
33 comprising the basal grade of land plants (mosses and ferns) and the second
34 comprising the most internal lineage of land plants (Conifers and flowering plants).
35 But independently of their split in two distinct branches of the DOGMA
36 tree, the Land Plants always show a higher number of functional genes in
37 their chloroplasts than the green algae from which they emerged, probably meaning that
38 terrestrial way of life necessitates more functional genes for an
39 optimal photosynthesis than marine way of life. But a more detailed
40 analysis of selected genes is necessary to better understad the reasons why?
