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PHYSICAL AND GENETIC ANALYSIS OF Ph1 GENE REGION ON
THE LONG ARM OF CHROMOSOME 5B IN WHEAT AND RELATED CEREALS
UMMARA WAHEED KHAN
AND MOHAMMAD MAROOF SHAH*
Abstract:
Genetic activity of Ph1 (pairing homoeologous) gene on
the long arm of chromosome 5B, blocks chromosome pairing during meiosis
in related genomes thus hindering the improvement in wheat on one hand
but guaranteeing stability of the genome during its evolution on the
other hand. Efforts have been made to clone this gene; however, complex
nature of the wheat genome and low density of markers in the region may
have been the prime reasons for no or low success in cloning this
important gene. We aimed to enrich Ph1 gene region by identifying
more markers through comparative mapping approaches. Twenty nine genetic
linkage and 12 physical maps in Triticeae (oat, rice, rye,
sugarcane, wheat, and barley) were used for comparative mapping.
Thirteen anchored markers that were previously mapped in the Ph1
gene region were used to identify additional markers in and around the
Ph1 gene region across Triticeae. Consensus physical and
genetic linkage maps were generated in wheat and related species for the
region. Using comparative mapping approaches, a total of
76 markers were identified in a rather larger
gene rich region (GRR) ‘5L0.5’ that contains the Ph1 gene region.
Of these 76 fifty six (56) were putatively mapped in 5L0.5 GRR whereas
33 were mapped in the Ph1 gene region. By comparing individual
consensus physical and genetic linkage maps it was observed that the
region is conserved among Triticeae and Poaceae from a
poor to fairly high density. Saturation mapping in the Ph1 gene
region will lead to eventually clone the gene which will have greater
impact in biological processes of life systems.
Biotechnology
Program, Department of Environmental Sciences, COMSATS Institute of
Information Technology (CIIT), Abbottabad, 25000, Pakistan
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