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Title: FREQUENCY AND VARIATION OF MICROSATELLITE MARKERS IN THE PAPAYA GENOME

Author
item EUSTICE, MORIAH - HARC
item Moore, Paul
item PRESTING, GERNOT - UNIVERSITY OF HAWAII
item MING, RAY - HARC

Submitted to: CTAHR Student Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 3/4/2005
Publication Date: 5/20/2005
Citation: Eustice, M., Moore, P.H., Presting, G., Ming, R. 2005. Frequency and variation of microsatellite markers in the papaya genome. CTAHR Student Research Symposium (Abstracts). P17.

Interpretive Summary: Abstract only.

Technical Abstract: Microsatellite or simple sequence repeat (SSR) markers are single locus markers that display co-dominant inheritance and are widely used in genetic mapping, gene tagging, and genetic diversity studies. Genomic research on papaya (Carica papaya L.) is rapidly advancing and has recently yielded significant quantities of sequence data. A total of 1.3 Mb random genomic sequences and 12.5 Mb bacterial artificial chromosome (BAC) end sequences were mined for SSR markers that were used to test for polymorphisms among the parents of three F2 populations. A total of 695 SSR markers have been identified with an average one SSR marker per 19.9 kb. Among them, 178 markers were classified as class I, or hypervariable markers that consisted of SSRs ' 20 bp, with an average of one class I SSR per 77.5 kb; 518 markers were classified as class II, or potentially variable markers that consisted of SSRs ' 12 < 20 bp, with an average of one class II SSR per 26.6 kb. Nine parental and F1 samples were tested for polymorphism with 91 SSR markers, including 60 class I SSRs and 31 Class II SSRs. The most polymorphic mapping population, with an average polymorphic rate of 43% for class I markers and 22.5% for class II markers, was derived from the Hawaii solo cultivar SunUp and an Australian unimproved variety Drew. Based on these results, we postulate that a total of 4800 class I and 13895 class II markers may exist in the papaya genome and that 5210 SSR markers could be mapped in the SunUp × Drew F2 population. These SSR markers and the genetic maps incorporating them will be widely applicable for papaya improvement.