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Genetics of Postzygotic Isolation in Eucalyptus: Whole-Genome Analysis of Barriers to Introgression in a Wide Interspecific Cross of Eucalyptus grandis and E. gobulus

journal contribution
posted on 2023-05-16, 15:59 authored by Myburg, AA, Vogl, C, Anthony Griffin, Sederoff, RR, Whetten, RW
The genetic architecture of hybrid fitness characters can provide valuable insights into the nature and evolution of postzygotic reproductive barriers in diverged species. We determined the genome-wide distribution of barriers to introgression in an F1 hybrid of two Eucalyptus tree species, Eucalyptus grandis (W. Hill ex Maiden.) and E. globulus (Labill.). Two interspecific backcross families (N = 186) were used to construct comparative, single-tree, genetic linkage maps of an F1 hybrid individual and two backcross parents. A total of 1354 testcross AFLP marker loci were evaluated in the three parental maps and a substantial proportion (27.7% average) exhibited transmission ratio distortion (α = 0.05). The distorted markers were located in distinct regions of the parental maps and marker alleles within each region were all biased toward either of the two parental species. We used a Bayesian approach to estimate the position and effect of transmission ratio distorting loci (TRDLs) in the distorted regions of each parental linkage map. The relative viability of TRDL alleles ranged from 0.20 to 0.72. Contrary to expectation, heterospecific (donor) alleles of TRDLs were favored as often as recurrent alleles in both backcrosses, suggesting that positive and negative heterospecific interactions affect introgression rates in this wide interspecific pedigree.

History

Publication title

Genetics

Volume

166

Pagination

1405-1418

ISSN

0016-6731

Department/School

School of Natural Sciences

Publisher

Genetics Society of America

Place of publication

United States

Repository Status

  • Restricted

Socio-economic Objectives

Native forests

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