@inbook {1971,
	title = {Thirty-Five Years of Thyme: A Tale of Two Polymorphisms},
	booktitle = {BioScience},
	volume = {48},
	year = {1998},
	month = {1998///},
	pages = {805 - 815},
	abstract = {The aromatic or wild thyme (Thymus vulgaris) is a small, woody shrub of the Labiatae family that inhabits open areas in the western Mediterranean basin. Two types of polymorphic variation exhibited by thyme have provided for the study of the evolutionary dynamics of genetic polymorphisms. First, wild thyme plants bear either female or hermaphrodite flowers but not both, which makes them gynodioecious. In southern France, populations exhibit female frequencies ranging from 5\% to more than 90\%, which is much higher than other gynodioecious species. Second, six different genetically determined monoterpene compositions of thyme{\textquoteright}s oil can be found in southern France. The authors John D. Thompson, Domenica Manicacci, and Michele Tarayre have synthesized 35 years of past research on the gynodioecy and oil compound variation of thyme in reference to the high frequency of females and number of oil compounds. The average female frequency of the thyme populations is approximately 60\%, which indicates cytoplasmic inheritance. Although nuclear genes are also involved in the determination of sexual phenotype, cytoplasmic sterility genes may block male function. Field investigations have determined that female frequency is correlated with population age, with young populations bearing a high number of females. The male function of nuclear genes is suspected of being restored from the sterility influence of cytoplasmic genes by appropriate alleles of restorer genes in the nuclear genome. The possibility that restorer alleles are lacking in patches of colonizing populations is suggested by the low levels of mitochondrial DNA and chloroplast DNA diversity in the populations. Studies have also shown that male-fertility restoration is more frequent when the females are pollinated by males of the original populations than for females cross-pollinated by distant populations. Other fitness considerations include a possible inbreeding depression among hermaphrodites, reduced seed production resulting from resource allocation toward pollen, and a variable sexual resource investment in hermaphrodites. Eleven species of the genus Thymus ranging from southeastern Spain to south-central France were studied by T. Adzet and others who found a pattern of geographic variation in their occurrence, with the three chemotypes of cineol, borneol, and camphene found in southeastern Spain; the phenolics of carvacrol and thymol abundant in northern Spain and southern France; and nonphenolics increasing in frequency toward the northern latitudes. The geographical distribution indicates an adaptive strategy whereby phenolic compounds are produced in response to hot, dry climates and nonphenolic compounds are produced in cool, moist habitats. The geographical distribution also occurs at a microhabitat scale according to microclimates and is thought to be in response to drought stress, interspecific competition, and herbivory},
	url = {http://muse.lib.auth.gr:9797/com/csa/?MuseHost=www-mi2.csa.com\&MuseFirst=1\&id=2\&recnum=2\&SID=686e18bda0daa536a33eb2d7c501c5dc\&MusePath=/ids70/view_record.php},
	author = {Tarayre, M and Thompson, J D and Manicacci, D}
}
@article {1879,
	title = {Spatial structure of nuclear factors involved in sex determination in the gynodioecious Thymus vulgaris L.},
	journal = {Journal of Evolutionary Biology},
	volume = {10},
	year = {1997},
	note = {From Duplicate 1 (                           Spatial structure of nuclear factors involved in sex determination in the gynodioecious Thymus vulgaris L.                         - Manicacci, D; Atlan, A; Couvet, D )                
},
	month = {1997///},
	pages = {889 - 907},
	publisher = {Wiley Online Library},
	address = {Affiliation: CEFE-CNRS, BP 5051, F-34033 Montpellier, France; Affiliation: Stn. de Genet. Veg., Ferme du Moulon, F-91190 Gif s/Yvette, France; Affiliation: Université de Paris VI, Dynamique du Génome et Evol., Tour 42, 4 place Jussieu, F-75251 Paris, },
	abstract = {Theoretical models have shown that the maintenance of high frequencies of females in gynodioecious species can be explained by the spatial structure of cytoplasmic and nuclear genes involved in sex determination. Whereas spatial structure of cytoplasmic factors which cause male-sterility has been studied in several taxa, that of nuclear factors that restore male-fertility (restoration factors) has received little attention. In this paper, we estimate spatial variation in the frequency of restoration factors associated with different cytoplasmic male-sterilities in the gynodioecious Thymus vulgaris. Clonal replicates of five female plants bearing at least four different male-sterilities and originating from five different populations (i.e., five cytogenotypes), were reciprocally transplanted into the original populations. Following open pollination at each site, seeds were harvested, germinated and grown to flowering. The frequency of hermaphrodites in each progeny was used to estimate the frequency of restoration factors in each population. For all cytogenotypes, there was marked variation in the rate of restoration among populations, indicating that spatial structure in nuclear restoration factors may influence the variation in female frequency in T. vulgaris. For three out of the five cytogenotypes, higher restoration rates were obtained for females introduced into their original population, which agrees with the theoretical prediction, under some hypotheses, that restoration factors are selected for in populations that contain the associated male-sterility (Gouyon and Couvet, 1985). The very low restoration rate in the progeny of one female clone in three populations indicates that stochastic events, such as founder effects, could lead to a local absence of restoration factors and thus the high female frequency (up to 90\%) observed in some populations. Differences among cytogenotypes suggest that some male-sterilities are associated with rarer restoration factors and are thus more likely to cause patches of females to develop in young populations.},
	keywords = {Cytoplasmic male-sterility, Gynodioecy, Nuclear restorer genes, Spatial structure, Thymus vulgaris},
	url = {http://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0031435743\&partnerID=40\&rel=R6.5.0},
	author = {Manicacci, D and Atlan, A and Couvet, D}
}
