Biology Reference
In-Depth Information
Lord Howe is an oceanic island in the Pacific region between Australia and New
Zealand. The ancestral form of
Howea
has existed for 4.5-5.5 myr (million years)
at Lord Howe Island; but
H. forsteriana
recently diverged from the species
H. bel-
moreana
by colonizing in the calcarenite soil
[20]
. Both
Howea
species are highly
homogenous and display very low genetic diversity. With the help of AFLP markers,
Savolainen et al. explain the sympatric speciation in
Howea
[20]
.
Johannesteijsmannia
lanceolata
and a few other species of the genus are endangered palms. Cross-
transferrable SSR markers developed in the genus are helpful in assessing heterozygos-
ity and population genetics of other species of the genus
[21]
.
Livistona carinensis
is a
vulnerable species limited to three locations in Africa. Nine SSR markers screened in
the species gave the diversity status of the populations and their conservation priori-
ties
[22]
. The geographical distribution of
Livistona
genus on both sides of the Wallace
Line near Australia provides interesting material for molecular phylogeny
[23]
. Based
on six chloroplast DNA regions and one nuclear DNA region,
Livistona mariae
and
L. rigida
were found to be identical across all loci sequenced (
Table 8.3
).
Double coconut, also called coco de mer (
Lodoicea maldivica
), is the largest-
bearing dioecious palm in the entire plant kingdom. A very high (99%) degree of
within-population AFLP diversity is seen in two island populations of the species,
and little genetic differentiation between populations
[24]
. Coco de mer also displays
high phenotypic plasticity and hence Dogley et al. suggest avoiding transferring
seeds between islands to foster diversity
[24]
. AFLP markers indicate the correlation
between genetic and geographical distance in sago palm
[25]
populations of Papua
New Guinea (
Table 8.3
).
8.4 Nypa, Oenocarpus, Pinanga, and Pseudophoenix
Nypa fruitcans
is an interesting palm belonging to monophyletic Nypoideae sub-
family and found in mangrove ecosystems. SSR and ISSR marker analyses indi-
cated the low genetic diversity in the species
[26]
. RAPD, ISSR markers
[27]
, and
PCR-RFLP of plastid DNA regions
[28]
were employed by Parani et al. to compare
the
Nypa
with other plant species in mangrove ecosystem (
Table 8.4
).
Oenocarpus
bacaba
is subcanopy arboreal palm distributed in the Amazon region that produces
edible fruits liked by birds and animals. The species also provides nutritional fruit
juice and oil
[29]
. SSR markers developed for the crop help in understanding the
mating system and paternity analysis
[29]
.
Pinanga
is a large genus and displays
variation in size and form
[30]
. Molecular phylogeny using the ITS region
[30]
of
the ribosomal gene indicates the monophyletic nature of the
Pinanga
genus. RAPD
markers in Indonesian populations of
P. javanica
indicate the genetic differentiation
due to hybridization among the six sympatric populations. Hence Witona, Masuda,
and Kondo
[31]
suggested both
in situ
and
ex situ
conservation of
Pinanga
. Genetic
diversity of
Pinanga
is correlated with population density (
Table 8.4
). Gene flow
among populations was high among the common species and low among the rare
ones
[32]
. Interestingly, Shapcott found all the species of
Pinanga
to be inbred but
genetically diverse
[32]
(
Table 8.4
).
