Gene flow between introduced and native Eucalyptus species: Early-age selection limits invasive capacity of exotic E. ovata×nitens F1 hybrids

2006 ◽  
Vol 228 (1-3) ◽  
pp. 206-214 ◽  
Author(s):  
R.C. Barbour ◽  
B.M. Potts ◽  
R.E. Vaillancourt
Keyword(s):  
Gene Flow ◽  
F1 Hybrids ◽  
Early Age ◽  
Eucalyptus Species ◽  
Invasive Capacity

scholarly journals Gene Flow Between Introduced and Native Eucalyptus Species: Morphological Analysis of Tri-Species and Backcross Hybrids Involving E. nitens

2007 ◽  
Vol 56 (1-6) ◽  
pp. 127-133 ◽  
Author(s):  
C. Barbour ◽  
B. M. Potts ◽  
R. E. Vaillancourt
Keyword(s):  
Gene Flow ◽  
Second Generation ◽  
Current Work ◽  
F1 Hybrids ◽  
Morphological Identification ◽  
Eucalyptus Species ◽  
Pure Species ◽  
Backcross Hybrids ◽  
In The Wild ◽  
Species Hybrids

Summary Morphometric analyses were conducted on second-generation tri-species and backcross hybrids in Eucalyptus. These hybrids were all produced using pollen from two E. nitens x cordata F1 hybrids and controlled pollination techniques. Tri-species hybrids were created with E. gunnii, E. ovata and E. viminalis as females, while backcrosses were produced with E. cordata. Multivariate analysis of seedling characteristics indicated that eighty percent of the backcross hybrids fell within the morphological range of E. cordata. All three cross combinations of the tri-species hybrids were biased away from E. nitens and towards their maternal parent and E. cordata. The inclusion of data for first-generation (F1) hybrids between the pure parental species in the current work showed the F1’s to be easily distinguishable from pure species, compared to second-generation hybrids. The use of morphology for detecting second-generation hybridisation involving exotic plantation species and native eucalypt populations will therefore be unreliable, and identifies a need for preventing second-generation hybrids from establish in the wild. The current work, nevertheless, provides further demonstration of the effectiveness of morphological identification of F1 hybrids. The easy recognition of F1 hybrids will be useful in identifying sites and species at risk of exotic gene flow and enable the development of weeding programs that focus on removing exotic hybrids in the wild.

Gene flow between introduced and native Eucalyptus species: crossability of native Tasmanian species with exotic E. nitens

2005 ◽  
Vol 53 (5) ◽  
pp. 465 ◽  
Author(s):  
R. C. Barbour ◽  
B. M. Potts ◽  
R. E. Vaillancourt
Keyword(s):  
Gene Flow ◽  
Native Species ◽  
Seed Set ◽  
Pollen Competition ◽  
F1 Hybrids ◽  
Eucalyptus Species ◽  
F1 Hybrid ◽  
Genetic Pollution ◽  
Morphometric Analyses ◽  
Natural Hybridisation

Eucalyptus nitens (Deane & Maiden) Maiden has been extensively introduced to the island of Tasmania for plantation purposes. Natural hybridisation with two native species has already been confirmed and this study aimed to determine which other Tasmanian native species could potentially hybridise with E. nitens. Controlled and supplementary pollinations with E. nitens pollen were undertaken on all Tasmanian native species that are potentially at risk of exotic gene flow and hence genetic pollution. Across the seven species tested by using controlled pollinations, seed set per flower, following E. nitens pollinations, was significantly less than for intraspecific outcross pollinations. No significant differences were evident in the percentage of seed that germinated or the percentage of germinants that grew into healthy seedlings in the glasshouse. Hybridity was verified by morphometric analyses and F1 hybrid seedlings were clearly differentiated from parental species and generally intermediate in morphology. Supplementary E. nitens pollination of open-pollinated native flowers was conducted to simulate natural pollination where pollen competition would occur. Seven of the fifteen species tested produced F1 hybrids in this case; however, further crossing is required to verify failed cross combinations. Although E. nitens can potentially hybridise with many native species, the results from both supplementary and controlled pollinations suggest the presence of post-pollination barriers of varying strength that need to be considered in assessing the risk of exotic gene flow from plantations.

scholarly journals Gene flow between introduced and native Eucalyptus species: exotic hybrids are establishing in the wild

2003 ◽  
Vol 51 (4) ◽  
pp. 429 ◽  
Author(s):  
R. C. Barbour ◽  
B. M. Potts ◽  
R. E. Vaillancourt
Keyword(s):  
Gene Flow ◽  
Native Species ◽  
Parental Species ◽  
F1 Hybrids ◽  
Eucalyptus Species ◽  
Eucalyptus Nitens ◽  
Natural Hybrids ◽  
In The Wild ◽  
Long Term Impact

F1 hybrids between exotic Eucalyptus nitens plantations and native E. ovata have previously been reported among seedlings grown from open-pollinated seed collected from E. ovata, on the island of Tasmania. Such exotic hybrid seedlings have now been found in the wild adjacent to plantations at three locations. The proportion of exotic hybrids in open-pollinated seed collected from nearby mature E. ovata was 5.5%. This level compares with only 0.4% for natural hybrids between native species at these sites (E. ovata, E. viminalis and E.�rodwayi). Detection of hybrids was initially based on their deviant morphology, which was generally intermediate between parental species. This subjective classification was then successfully verified by morphometric and allozyme analyses. Pure E. nitens seedlings (wildlings) were restricted to within 30 m of these plantations, whereas established hybrids were found up to 310 m from the plantations. This pattern of establishment reflects dispersal of exotic seed and pollen respectively. It is likely that the recent expansion of the eucalypt plantation estate in Australia will cause an increase in the frequency of exotic hybrids. However, the long-term impact of such hybridisation is yet to be assessed.

scholarly journals Speciation in the presence of gene flow: population genomics of closely related and diverging Eucalyptus species

Heredity ◽  
2018 ◽  
Vol 121 (2) ◽  
pp. 126-141 ◽  
Author(s):  
Susan Rutherford ◽  
Maurizio Rossetto ◽  
Jason G. Bragg ◽  
Hannah McPherson ◽  
Doug Benson ◽  
...  
Keyword(s):  
Gene Flow ◽  
Population Genomics ◽  
Eucalyptus Species

Contrasting Success of Natural Hybridization in Two Eucalyptus Species Pairs

1980 ◽  
Vol 28 (2) ◽  
pp. 167 ◽  
Author(s):  
DW Drake
Keyword(s):  
Principal Component ◽  
Flowering Phenology ◽  
Natural Hybridization ◽  
F1 Hybrids ◽  
Hybrid Population ◽  
Eucalyptus Species ◽  
Major Barrier ◽  
Species Pairs ◽  
Plant Hybridization ◽  
Hybrid Number

A morphological study with univariate and principal component analyses of mature tree and open-pollinated seedling populations shows that natural hybridization is occurring between Eucalyptus melanophloia and E. crebra, and E. populnea and E. crebra (subgenus Symphyomyrtus, section Adnataria). The level of successful hybridization in these two systems, where fundamental genetic (reproductive) and ecological (habitat and spatial) barriers are absent, is examined. Within the ecotone, hybrids between E. melanophloia and E. crebra are about one-fifth as frequent as those between E. populnea and E. crebra. Analyses of the phenotype/genotype compositions of the hybrid populations, the patterns of segregation, and outcrossing frequencies between the species pairs indicate the level of development of the hybrid populations. All E. melanophloia × E. crebra hybrids appear to be F1 hybrids. In contrast, the E.populnea x E. crebra hybrid population attains a much higher level of development in terms of both hybrid number and genotypic complexity. Flowering phenology is a major barrier to E. melanophloia × E. crebra hybrid formation compared with the other hybrids, although it is considered an incomplete barrier and alone may not explain the diversity of hybrid success which occurs.A theory of plant hybridization which incorporates the concept of hybridization success is presented and discussed in relation to the two hybridizing systems, as a basis for further investigating the mechanisms involved.

scholarly journals Pure species discriminate against hybrids in the Drosophila melanogaster species subgroup

2020 ◽  
Author(s):  
Antonio Serrato-Capuchina ◽  
Timothy D. Schwochert ◽  
Stephania Zhang ◽  
Baylee Roy ◽  
David Peede ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Flow ◽  
Parental Species ◽  
Cuticular Hydrocarbon ◽  
F1 Hybrids ◽  
Sexual Attractiveness ◽  
Pure Species ◽  
Species Pairs ◽  
Fertile Hybrids ◽  
Drosophila Melanogaster Species Subgroup

ABSTRACTIntrogression, the exchange of alleles between species, is a common event in nature. This transfer of alleles between species must happen through fertile hybrids. Characterizing the traits that cause defects in hybrids illuminate how and when gene flow is expected to occur. Inviability and sterility are extreme examples of fitness reductions but are not the only type of defects in hybrids. Some traits specific to hybrids are more subtle but are important to determine their fitness. In this report, we study whether F1 hybrids between two species pairs of Drosophila are as attractive as the parental species. We find that in both species pairs, the sexual attractiveness of the F1 hybrids is reduced and that pure species discriminate strongly against them. We also find that the cuticular hydrocarbon (CHC) profile of the hybrids is intermediate between the parental species. Perfuming experiments show that modifying the CHC profile of the hybrids to resemble pure species improves their chances of mating. Our results show that behavioral discrimination against hybrids might be an important component of the persistence of species that can hybridize.

scholarly journals Evaluating the accuracy of genomic prediction of growth and wood traits in two Eucalyptus species and their F1 hybrids

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Biyue Tan ◽  
Dario Grattapaglia ◽  
Gustavo Salgado Martins ◽  
Karina Zamprogno Ferreira ◽  
Björn Sundberg ◽  
...  
Keyword(s):  
Genomic Prediction ◽  
F1 Hybrids ◽  
Eucalyptus Species ◽  
Wood Traits

scholarly journals Cre-dependent optogenetic transgenic mice without early age-related hearing loss

2018 ◽  
Author(s):  
Daniel Lyngholm ◽  
Shuzo Sakata
Keyword(s):  
Hearing Loss ◽  
Transgenic Mice ◽  
Genetic Defect ◽  
F1 Hybrids ◽  
Early Age ◽  
F1 Hybrid ◽  
Hearing Research ◽  
Brain Functions ◽  
Age Related ◽  
Age Related Hearing Loss

AbstractWith the advent of recent genetic technologies for mice, it is now feasible to investigate the circuit mechanisms of brain functions in an unprecedented manner. Although transgenic mice are commonly used on C57BL/6J (C57) background, hearing research has typically relied on different genetic backgrounds, such as CBA/Ca or CBA due to the genetic defect of C57 mice for early age-related hearing loss. This limits the utilization of available genetic resources for hearing research. Here we report congenic (>F10) Cre-dependent channelrhodopsin2 (ChR2) mice on CBA/Ca background. By crossing this line with Cre-driver mice on C57 background, F1 hybrids restored the hearing deficit of C57 mice. We also found a linear relationship between aging and hearing loss, with progression rates varied depending on genetic backgrounds (3.39 dB/month for C57; 0.82 dB/month for F1 hybrid). We further demonstrate that this approach allows to express ChR2 in a specific type of inhibitory neurons in the auditory cortex and that they can be identified within a simultaneously recorded population of neurons in awake mice. Thus, our Cre-dependent optogenetic transgenic mice on CBA/Ca background are a valuable tool to investigate the circuit mechanisms of hearing across lifespan.

scholarly journals Landscape and taxon age are associated with differing patterns of hybridization in two Eucalyptus (Myrtaceae) subgenera

2020 ◽  
Vol 127 (1) ◽  
pp. 49-62
Author(s):  
T P Robins ◽  
R M Binks ◽  
M Byrne ◽  
S D Hopper
Keyword(s):  
Evolutionary Process ◽  
F1 Hybrids ◽  
Divergence Times ◽  
Eucalyptus Species ◽  
Reproductive Barriers ◽  
Nucleotide Polymorphism ◽  
Plant Populations ◽  
Single Nucleotide ◽  
Clonal Spread

Abstract Background and Aims Hybridization is an important evolutionary process that can have a significant impact on natural plant populations. Eucalyptus species are well known for weak reproductive barriers and extensive hybridization within subgenera, but there is little knowledge of whether patterns of hybridization differ among subgenera. Here, we examine eucalypts of Western Australia’s Stirling Range to investigate how patterns of hybridization are associated with landscape and taxon age between the two largest Eucalyptus subgenera: Eucalyptus and Symphyomyrtus. In doing so, we tested a hypothesis of OCBIL (old, climatically buffered, infertile landscape) theory that predicts reduced hybridization on older landscapes. Methods Single nucleotide polymorphism markers were applied to confirm the hybrid status, parentage and genetic structure of five suspected hybrid combinations for subg. Eucalyptus and three combinations for subg. Symphyomyrtus. Key Results Evidence of hybridization was found in all combinations, and parental taxa were identified for most combinations. The older parental taxa assessed within subg. Eucalyptus, which are widespread on old landscapes, were identified as well-defined genetic entities and all hybrids were exclusively F1 hybrids. In addition, many combinations showed evidence of clonality, suggesting that the large number of hybrids recorded from some combinations is the result of long-term clonal spread following a few hybridization events rather than frequent hybridization. In contrast, the species in subg. Symphyomyrtus, which typically occur on younger landscapes and are more recently evolved, showed less distinction among parental taxa, and where hybridization was detected, there were high levels of introgression. Conclusions Reduced hybridization in subg. Eucalyptus relative to extensive hybridization in subg. Symphyomyrtus affirmed the hypothesis of reduced hybridization on OCBILs and demonstrate that clade divergence times, landscape age and clonality are important drivers of differing patterns of speciation and hybridization in Eucalyptus.

scholarly journals Exploring the potential of gametic reconstruction of parental genotypes by F1 hybrids as a bridge for rapid introgression

Genome ◽  
2017 ◽  
Vol 60 (9) ◽  
pp. 713-719 ◽  
Author(s):  
Charles H. Cannon ◽  
C. Lane Scher
Keyword(s):  
Gene Flow ◽  
Genomic Structure ◽  
Natural Populations ◽  
Genomic Analysis ◽  
F1 Hybrids ◽  
Phenotypic Traits ◽  
Crossing Over ◽  
Genetic Introgression ◽  
Apparent Paradox ◽  
Interspecific Gene Flow

Interspecific hybridization and genetic introgression are commonly observed in natural populations of many species, especially trees. Among oaks, gene flow between closely related species has been well documented. And yet, hybridization does not lead to a “melting pot”, i.e., the homogenization of phenotypic traits. Here, we explore how the combination of several common reproductive and genomic traits could create an avenue for interspecific gene flow that partially explains this apparent paradox. During meiosis, F1 hybrids will produce approximately (½)n “reconstructed” parental gametes, where n equals the number of chromosomes. Crossing over would introduce a small amount of introgressive material. The resulting parental-type gametophytes would probably possess a similar fertilization advantage as conspecific pollen. The resulting “backcross” would actually be the genetic equivalent of a conspecific out-cross, with a small amount of heterospecific DNA captured through crossing over. Even with detailed genomic analysis, the resulting offspring would not appear to be a backcross. This avenue for rapid introgression between species through the F1 hybrid will be viable for organisms that meet certain conditions: low base chromosome number, conserved genomic structure and size, production of billions of gametes/gametophytes during each reproductive event, and conspecific fertilization advantage.

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