Population Genetic Structure in Agamospermous Plants

Gornall, R. J.

doi:10.1201/9781439833278.ch7

Cited by 46 publications

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“…These patterns are consistent with the processes generating diversity in apomictic species (Gornall 1999). It seems that multiple hybridization events have had a major role in the generation of genetic diversity in L. dufourii .…”

Section: Discussionsupporting

confidence: 86%

“…Although apomictic taxa may withstand population bottlenecks and restore population sizes from just a few individuals, genetic diversity is recovered more slowly than in their sexually reproducing diploid relatives, and this could ultimately compromise their long‐term survival (Richards 2003). The loss of entire populations can have more serious consequences given the strong genetic differentiation of apomictic populations (Gornall 1999).…”

Section: Introductionmentioning

confidence: 99%

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Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

2007

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Microsatellite markers were used to evaluate the genetic diversity and population genetic structure in the critically endangered Limonium dufourii (Plumbaginaceae), a highly endemic triploid species from the coasts of eastern Spain. Sixty-five alleles from 13 microsatellite regions were amplified in a sample of 122 individuals collected from the six extant populations. Microsatellite patterns were consistent with the triploid nature of L. dufourii. Alleles were unambiguously assigned to two different parental subgenomes in this hybrid species and the greater contribution of the diploid parental subgenome was confirmed. Eleven, 25 and 26 multilocus genotypes were recorded from the haploid, diploid and from the combined information of both subgenomes, respectively. Genetic diversity was mostly distributed among populations (72.06% of the total genetic variation). Genotypes from Marjal del Moro populations grouped into two highly structured clusters (88.41% of the total variance). The observed patterns of distribution of genetic diversity are interpreted to result from multiple hybridization events and isolation between populations. Threats to this species are mainly anthropogenic (urbanization and tourism pressure), although stochastic risks cannot be ignored. Therefore, in order to preserve extant genetic variation of L. dufourii, in situ strategies such as the preservation of its habitat are a high priority. Several recommendations in order to assist ex situ measures to guarantee the success of conservation strategies and maintain the relationships between individuals and populations are proposed.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

2007

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“…This is where the seeds are produced without fertilisation and by processes that bypass the normal meiotic cycle (Hayward 1999). There has been renewed interest recently in apomictic plants, with some progress being made in unravelling the taxonomic (Campbell 1999), breeding behaviour (Gornall 1999) and evolutionary relationships within the 33 plant families that exhibit apomixis (Carmen 1997). Additionally, studies of the underlying genetic mechanism of apomixis have been undertaken, to explore the possibility of transferring apomixis genes into crop plants (Hayward 1999).…”

Section: Introductionmentioning

confidence: 99%

The origin of intermediate species of the genus Sorbus

2002

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The genus Sorbus in Europe contains five diploid species, Sorbus aria, Sorbus aucuparia, Sorbus torminalis, Sorbus chamaemespilus and Sorbus domestica, classified into five different subgenera. The subgenus Aria (or the S. aria aggregate) contains apomictic triploid and tetraploid species. Within the genus there are, in addition, a number of species, morphologically intermediate between plants of the four main subgenera, which are considered to reproduce partly, or exclusively, by apomixis. These are believed to have originated by hybridisation between species in the S. aria aggregate and a species from another subgenus (either S. aucuparia, S. torminalis or S. chamaemespilus). We have used restriction fragment length polymorphism (RFLP) analysis on a total of 178 Sorbus accessions to test this model. The genome relationships of the different groups have been assessed, and the hybrid nature of the major intermediate groups is unequivocally demonstrated. Polyploid species in the S. aria aggregate show genetic variation, indicating the possibility of multiple origins and/or facultative apomictic breeding behaviour. A major finding, confirmed by microsatellite analysis, is that the 'intermediate' species S. intermedia is shown to have genomes from S aria, S aucuparia and S torminalis. Polymorphic mitochondrial DNA markers were used to determine the direction of the crosses that gave rise to new 'hybrid species'; in the majority of cases the pollen was provided by the parent from the S aria aggregate.

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“…In addition, crossing experiments using some sexual strains were carried out to test induction of apomixis. Because allopolyploidy is frequently related to apomixis in land plants (Wagner and Wagner 1980, Gornall 1999, Richards 2003), ploidy level was also compared between some apomictic strains and their sexual relatives.…”

mentioning

confidence: 99%

Induction of Apomixis by Outcrossing Between Genetically Divergent Entities of Caloglossa Leprieurii (Ceramiales, Rhodophyta) and Evidence of Hybrid Apomicts in Nature1

Kamiya

West

Hara

2011

Journal of Phycology

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Our previous study revealed that apomixis, recycling of tetrasporophytes, can be generated through outcrossing between genetically divergent entities of Caloglossa monosticha M. Kamiya, though such apomicts have never been found in nature. In the case of C. leprieurii (Mont.) G. Martens, the most widespread species in this genus, many apomictic strains have been isolated worldwide, but it is unknown whether these apomicts evolved through an outcrossing process similar to that in C. monosticha. In this study, heterogeneity of the apomicts and their sexual relatives as well as their evolutionary relationships was examined using the nuclear-encoded actin gene and plastid-encoded RUBISCO spacer region. Thirteen out of 18 apomictic strains were heterogeneous and contained divergent actin alleles, whereas only two out of 23 sexual strains were heterogeneous. The five homogeneous apomicts were genetically identical, or quite similar, to the sexual strains isolated from adjacent sites. Furthermore, three of the five homogeneous apomicts frequently produced tetraspores that grew into gametophytes, while all the heterogeneous apomicts never generated gametophytes. Apomictic strains from Florida were allotriploid, and each of the three actin sequences was closely related to those of sexual strains from Florida, Peru, and Mexico/Guatemala. In crossing tests, obligate apomixis was generated through the outcrossing between the male from Madagascar and the female from the northwestern Atlantic. These results suggest that outcrossing between genetically divergent sexual entities is one factor that induces apomixis in C. leprieurii.

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Population Genetic Structure in Agamospermous Plants

Cited by 46 publications

References 0 publications

Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

Historical and biological determinants of genetic diversity in the highly endemic triploid sea lavender Limonium dufourii (Plumbaginaceae)

The origin of intermediate species of the genus Sorbus

Induction of Apomixis by Outcrossing Between Genetically Divergent Entities of Caloglossa Leprieurii (Ceramiales, Rhodophyta) and Evidence of Hybrid Apomicts in Nature1

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