Lsozyme Assessment of the Relationships Between Guizotia Abyssinica (L.I) Casso And Its Close wild Relatives
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Date
2006-07
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Addis Ababa University
Abstract
In this study, 13 popula~ions, representing six species/taxa of GuizOlia were compared using
isozyme markers. The three enzyme systems, aspartate aminotransferase (AAT, B.C. 2.6.1.1),
acid phosphatase (ACP, E.C. 3.1.3.2) and phosphoglucose isomerase (PG!, B.C. 5.3.1.9) were
used to study the genetic variation of the cultivated G. abY.I'.I'illica and live related wild taxa
/species belonging to Gu;zo/i(f. Eeven if, most of these taxa share l'0111111011 morphological and
cytological features, the genetic bases of differences distinguishing them have not been
determined. The electrolihoretie study was initiated to assess the degree of divergences or
genetic identities among these closely related groups of taxa with the possible identitlcation oj'
progenitor for the cultivated species, G. abyssinica. All the taxa/speices were analyzed, using
horizontal starch gel electrophoresis. We found three AAT, two ACP and two PGI isozyme
zones in all species /taxa except G. arborescens (has foul' PGI isozyme zones) in the studied
materials and hence a total of eight loci were assessed. Since all species/taxa are assumed to be
outcrossing, the gcnetic diversity within population is greatcr than among populations. A high
level of genetic variation and low level of genetic differcntiation among populations were
found in all species /taxa except G. arborescel1.1'. Chelelu is recently identified population and
show high genetic diversity than other studied material probably due to its adjacent growth with
widespread G. .I'cabra ssp schimperi and other related species may be favoured for its
variability through introgression or due to its unique history. G. abyssinial and Chelelu showed
low genetic distance tilan the genetic distance of G. abyssiJlinia and G. scabr" ssp schiJllperi at
genes specifying the three enzyme systems. The idea of progenitor-derivative species pairs
between C. abysillica and Chelclu is supported by th~ high genetic identity values(l = 0.9305).
Furthermore, the putative derivative C. abysinica has similar allele with the possible progcnitor
Chelelu population. Most alleles whieh were found in G. abysillica are also found in Chelelu.
The aliozyme diversity indicated that Chelelu is the most probable proginetors of G. abysiniCil .
Likewise, the isozyme study showed that there were close relationships among G. a!Jyssynic(l.
G.scabra ssp schiJllperi ancl Chelelu population, and between G. scahra ssp scabra alld G.
villosa in support of the karyotype and pollen fertility studies in the gellus Gillzolia. The
genetic marker used in this study also indicated that G. arborescells was the most divergent
taxa among the studied materials which is in line with the cytological and morphlogical studies
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Biology