An integrated genetic map of Populus deltoides based on amplified fragment length polymorphisms
R. L. Wu (1)(2), Y. F. Han (2), J. J. Hu (2), J. J. Fang (2), L. Li (2)(2), M. L. Li (2), Z. -B. Zeng (1)
(1) Program in Statistical Genetics,
Department of Statistics, North Carolina State University, Raleigh, NC
27695-8203 USA e-mail:rwu@statgen.ncsu.edu
Fax: +1-919-515-7315 + 86
(2) Research Institute of Forestry,
Chinese Academy of Forestry, Beijing 100091 China
Received: 10 September 1999 / Accepted: 3 November 1999
Abstract Amplified fragment length
polymorphism (AFLP) is an efficient molecular technique for generating
a large
number of DNA-based genetic markers
in Populus. We have constructed an integrated genetic map for a Populus
backcross population derived from
two selected P. deltoides clones using AFLP markers. A traditional strategy
for
genetic mapping in outcrossing
species, such as forest trees, is based on two-way pseudo-testcross configurations
of
the markers (testcross markers)
heterozygous in one parent and null in the other. By using the markers
segregating in
both parents (intercross markers)
as bridges, the two parent-specific genetic maps can be aligned. In this
study, we
detected a number of non-parental
heteroduplex markers resulting from the PCR amplification of two DNA segments
that have a high degree of homology
to one another but differ in their nucleotide sequences. These heteroduplex
markers detected have served as
bridges to generate an integrated map which includes 19 major linkage groups
equal
to the Populus haploid chromosome
number and 24 minor groups. The 19 major linkage groups cover a total of
2,927 cM, with an average spacing
between two markers of 23. 3 cM. The map developed in this study provides
a
first step in producing a highly
saturated linkage map of the Populus deltoides genome.
Key words AFLP · Heteroduplex · Intercross marker · Linkage map · Populus deltoides · Testcross marker