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A sex‐linked SCAR marker in Bryonia dioica (Cucurbitaceae), a dioecious species with XY sex‐determination and homomorphic sex chromosomes
Author(s) -
OYAMA R. K.,
VOLZ S. M.,
RENNER S. S.
Publication year - 2009
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2008.01641.x
Subject(s) - biology , plant reproductive morphology , dioecy , sex linkage , genetics , genetic marker , population , botany , chromosome , gene , pollen , demography , sociology
Genetic crosses between the dioecious Bryonia dioica (Cucurbitaceae) and the monoecious B. alba in 1903 provided the first clear evidence for Mendelian inheritance of dioecy and made B. dioica the first organism for which XY sex‐determination was experimentally proven. Applying molecular tools to this system, we developed a sex‐linked sequence‐characterized amplified region (SCAR) marker for B. dioica and sequenced it for individuals representing the full geographic range of the species from Scotland to North Africa. For comparison, we also sequenced this marker for representatives of the dioecious B. cretica , B. multiflora and B. syriaca , and monoecious B. alba . In no case did any individual, male or female, yield more than two haplotypes. In northern Europe, we found strong linkage between our marker and sex, with all Y‐sequences being identical to each other. In southern Europe, however, the linkage between our marker and sex was weak, with recombination detected within both the X‐ and the Y‐homologues. Population genetic analyses suggest that the SCAR marker experienced different evolutionary pressures in northern and southern Europe. These findings fit with phylogenetic evidence that the XY system in Bryonia is labile and suggest that the genus may be a good system in which to study the early steps of sex chromosome evolution.