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Characterising microsatellite loci in the blue crane (Grus paradisea)Meares, Kathleen Frances. January 2007 (has links)
The blue crane (Grus paradisea) is endemic to southern Africa and has the smallest
geographical range of the 15 crane species occurring world-wide. Although this species is still
found throughout most of its historic range, it has experienced a significant and rapid decline in
numbers over the last 20 years. One factor causing this decline is the illegal removal of chicks
from the wild. Permits are required to keep, trade in and breed cranes in captivity. However,
birds must be captive bred in order to obtain a permit. Therefore, chicks taken illegally from the
wild are fraudulently incorporated into an existing captive population under the pretence that
they offspring of a legal captive pair. This study describes the development of a set of
microsatellite markers to assist the identification of illegal trade in the blue crane. These
markers can ultimately be used to verify the relationship between the offspring and its claimed
parents by performing parentage analyses. Forty microsatellite loci were obtained from
genomic libraries previously developed in two other crane species and tested for cross-species
utility in the blue crane. In addition, 42 loci were developed for this study from a blue crane
species-specific genomic microsatellite library, of which 19 were tested for polymorphism in
this species. The microsatellite markers characterised here were also tested for their utility in
two other crane species: wattled crane (G. carunculatus) and grey-crowned crane (Balearica
regulorum). One locus, Gamu007, was found to be sex-linked and therefore excluded from the
set of markers. A total of 28 polymorphic loci were tested for the suitability in parentage
analysis in the blue crane. Of these, a set of 16 loci were determined to be as suitable for this
purpose. These loci were shown to be inherited in a Mendelian fashion in a single blue crane
family. In addition, statistical analysis of the loci were identified as exhibiting linkage
equilibrium, this was supported by their distant association on a predicted Grus microsatellite
map based on the chicken genome. The selected loci were also identified as having a low
frequency of null alleles as well as a total first and second parent exclusion power of 0.9999
and 1.0000, respectively. These loci provide a valuable tool for parentage testing in blue crane,
and may also be valuable in population genetic studies to assist conservation strategies. In
addition, this set may be used to assist legal cases involving the illegal trade in blue cranes
upon completion of additional microsatellite marker validation procedures. Twenty-seven loci
were polymorphic in the wattled and grey-crowned crane. These could provide a valuable
source of micro satellite loci in these species, and could potentially eliminate the need for the
development of a species-specific microsatellite library. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.
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Investigation of the utilization of microsatellites for fingerprinting in three endangered southern African crane species.Moodley, Eshia Stephany. January 2006 (has links)
Cranes are large elegant birds that occur on all continents of the world except for
South America and Antarctica. Of the fifteen species of crane worldwide, three
predominantly occur in southern Africa; the Wattled crane (Bugeranus carunculatus),
the Blue crane (Anthropoides paradisea) and the Crowned crane (Balearica
regulorum). Crane numbers throughout the world are diminishing, mostly because of
the destruction of their habitat and illegal bird trading. Efforts are underway to
prevent species extinction, legally and through the compilation of a studbook that
contains descriptions of physical attributes, ownership, location and possible
kinships of birds in captivity . This investigation, first of its kind, WdS undertaken to
assess whether twelve published and unpublished microsatellite primers developed
for the related Whooping crane and Red-Crowned crane could be used to fingerprint
the southern African crane species using cost effective polyacrylamide gel
electrophoresis. The results obtained were then used to determine the extent of
genetic variation within species and distance between species.
All primer sets amplified heterologous microsatellite loci in the three crane species,
however, the unpublished primers produced poorly defined fingerprints even after
extensive optimization. Of the twelve microsatellite loci investigated, the Blue crane
and the Wattled crane revealed a high level of polymorphism. The Blue crane
displayed 76% polymorphism and the Wattled crane 92%. In contrast, for the
Crowned crane, that belongs to a different subfamily, Balearicinae, only 50% of the
loci were polymorphic. The alleles displayed sizes similar to that of the species for
which the primers were developed. Little variation in size, less than 10 bp, was noted
for the different alleles of the polymorphic loci. The number of alleles, on the other
hand, at each of the polymorphic loci was found to be low. The frequency of the
most prevalent allele at most of the loci was generally reasonably high. These
results therefore suggest that these primer sets are not suitable for individual
identification and differentiation using polyacrylamide gel electrophoresis.
Xll
The observed heterozygosity of the three crane species was low; 12% in Blue crane;
7% in Crowned crane; and 13% in Wattled crane. Nei's identity further confirmed the
high similarity between individuals; 66-100% for Blue crane; 55-100% for Crowned
crane and 41-95% for Wattled crane. This low genetic variation is attributed to
possible relatedness between birds supplied by aviculturists whom have a limited
number of birds in captivity. A Hardy-Weinberg test for equilibrium revealed that
most of the microsatellite loci displayed a deficiency of heterozygotes, while a few
loci displayed an excess of heterozygotes. In general, the Hardy Weinberg test of
equilibrium supported the notion that the individuals within each of the species might
have been related.
Differentiation between the three crane species ranged from 3-5%, with Blue and
Wattled crane displaying a higher degree of genetic similarity when compared to the
Crowned crane, known to be the oldest extant crane species.
The limited allelic variation within the microsatellite loci tested, as well as the
extensive genetic similarity between individuals suggests that a wide-ranging search
for additional microsatellite loci that are more polymorphic and contain a larger
number of alleles should be undertaken for the southern African crane species. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.
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