Genetic analysis of an interspecific hybrid swarm of Populus: occurrence of unidirectional introgression.
Restriction fragment length polymorphisms were used to distinguish genotypes of two species of Populus, P. fremontii ('Fremont') and P. angustifolia ('narrowleaf'). Both inter- and intraspecific polymorphisms were detected in these cottonwood trees. The interspecific variation was much greater than the intraspecific variation. This permitted identification of parental genotypes within individual trees of a hybrid swarm which exists in an overlap zone between the two species. Within this hybrid swarm, individual trees are either F1 hybrids or backcrosses with a pure 'narrowleaf' parent; no progeny were found that could be attributed to crossing between F1 hybrid trees, or to backcrossing between F1 hybrid trees and 'Fremont'.
Keim
P
P
Department of Biology, University of Utah, Salt Lake City 84112.
Paige
K N
KN
Whitham
T G
TG
Lark
K G
KG
D003433:Crosses, Genetic; D004587:Electrophoresis, Agar Gel; D008040:Genetic Linkage; D005828:Genetics, Population; D006824:Hybridization, Genetic; D012150:Polymorphism, Restriction Fragment Length; D014197:Trees