Electrophoretic evidence for tetrasomic inheritance in the dioecious tree Maclura pomifer (Raf.) Schneid
1996
Laushman, R.H. | Schnabel, A. | Hamrick, J.L.
Although polyploidy is recognized as an important feature of chromosomal evolution, natural autopolyploids rarely occur compared to allopolyploids. Enzymes coded by four electrophoretic loci (Lap, Pgm-1, Pgi-2, and Tpi-2) in adults and full-sib progeny indicate tetrasomic inheritance in the dioecious tree Maclura pomifera, strongly suggesting that this species is an autopolyploid. This study is the first to document tetrasomic inheritance in a dioecious tree. Five of 19 segregation arrays deviated significantly from expected tetrasomic ratios, whereas 11 of 19 deviated significantly from digenic disomic expectations. We observed 22 double-reduction genotypes, which provides a likely source of deviation from expected tetrasomic frequencies. We suggest that unusual patterns of sexual expression in this species are related to autopolyploidy through production of unbalanced sex chromosome ratios.
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