Big Baby, Little Mother: Tsetse Flies Are Exceptions to the Juvenile Small Size Principle.

While across the animal kingdom offspring are born smaller than their parents, notable exceptions exist. Several dipteran species belonging to the Hippoboscoidea superfamily can produce offspring larger than themselves. In this essay, the blood-feeding tsetse is focused on.

"Born to Run"? Not Necessarily: Species and Trait Bias in Persistent Free-Living Transgenic Plants.

The possibility of transgenes from engineered plants ending up in unmanaged populations with undesirable consequences has been a long-term biosafety concern. Experience with traditionally improved plants reveals that most cases of such gene escape have been of little consequence, but on occasion they have led to the evolution of problematic plants or have resulted in an increased extinction risk for wild taxa. Three decades have passed since the first environmental release of transgenic plants, and more than two decades since their first commercialization.

Does introgression of crop alleles into wild and weedy living populations create cryptic in situ germplasm banks?

Natural gene flow often delivers alleles from cultivated species into unmanaged populations of weedy or wild relatives. Unmanaged populations with introgressed crop alleles may become the unintended repositories of crop alleles that are no longer available to breeders. Descriptive studies have confirmed the introgression of alleles from 17 crop species into free-living populations.

Genetic structure reveals a history of multiple independent origins followed by admixture in the allopolyploid weed Salsola ryanii.

It has recently become clear that many invasive species have evolved in situ via hybridization or polyploidy from progenitors which themselves are introduced species. For species formed by hybridization or polyploidy, genetic diversity within the newly formed species is influenced by the number of independent evolutionary origins of the species. For recently formed species, an analysis of genetic structure can provide insight into the number of independent origin events involved in the formation of the species.

Fitness correlates of crop transgene flow into weedy populations: a case study of weedy rice in China and other examples.

Whether transgene flow from crops to cross-compatible weedy relatives will result in negative environmental consequences has been the topic of discussion for decades. An important component of environmental risk assessment depends on whether an introgressed transgene is associated with a fitness change in weedy populations. Several crop-weed pairs have received experimental attention.

Maize Germplasm Conservation in Southern California's Urban Gardens: Introduced Diversity Beyond and Management.

Contemporary germplasm conservation studies largely focus on and management of diversity within centers of genetic diversity. Transnational migrants who transport and introduce landraces to new locations may catalyze a third type of conservation that combines both approaches. Resulting populations may support reduced diversity as a result of evolutionary forces such as genetic drift, selection, and gene flow, yet they may also be more diverse as a result of multiple introductions, selective breeding and cross pollination among multiple introduced varietals.

Rapid range expansion of a newly formed allopolyploid weed in the genus Salsola.

Premise Of The Study: Newly formed species (neospecies) can experience a variety of demographic fates, ranging from rapid invasive expansion to rapid extinction. Here we investigate the fate of the neospecies Salsola ryanii 10 years after its initial discovery in the Central Valley of California, USA. This species is an allopolyploid derived via hybridization between the invasive species, S.

Risk assessment of gene flow from genetically engineered virus resistant cassava to wild relatives in Africa: an expert panel report.

The probability and consequences of gene flow to wild relatives is typically considered in the environmental risk assessment of genetically engineered crops. This is a report from a discussion by a group of experts who used a problem formulation approach to consider existing information for risk assessment of gene flow from cassava (Manihot esculenta) genetically engineered for virus resistance to the 'wild' (naturalized) relative M. glaziovii in East Africa.

Novel seed protection in the recently evolved invasive, California wild radish, a hybrid Raphanus sp. (Brassicaceae).

Unlabelled: •

Premise Of The Study: Interspecific hybridization may have considerable effects on plant structural defenses that can contribute to the success of invasive hybrid lineages. Changes in fruit structural and material properties are predicted to have key effects on predispersal granivory.•

Methods: Here, we asked whether plant structure can increase the fitness of a hybrid invasive relative to its progenitors.

Is gene flow the most important evolutionary force in plants?

Although theory has demonstrated rather low levels of gene flow are sufficient to counteract opposing mutation, drift, and selection, widespread recognition of the evolutionary importance of gene flow has come slowly. The perceived role of gene flow as an evolutionary force has vacillated over the last century. In the last few decades, new methods and analyses have demonstrated that plant gene flow rates vary tremendously-from nil to very high-depending on the species and specific populations involved, and sometimes over time for individual populations.

Taxonomic and life history bias in herbicide resistant weeds: implications for deployment of resistant crops.

Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resistance and others do not is poorly understood.

The genomic signature of crop-wild introgression in maize.

The evolutionary significance of hybridization and subsequent introgression has long been appreciated, but evaluation of the genome-wide effects of these phenomena has only recently become possible. Crop-wild study systems represent ideal opportunities to examine evolution through hybridization. For example, maize and the conspecific wild teosinte Zea mays ssp.

Sequence polymorphisms in wild, weedy, and cultivated rice suggest seed-shattering locus sh4 played a minor role in Asian rice domestication.

The predominant view regarding Asian rice domestication is that the initial origin of nonshattering involved a single gene of large effect, specifically, the sh4 locus via the evolutionary replacement of a dominant allele for shattering with a recessive allele for reduced shattering. Data have accumulated to challenge this hypothesis. Specifically, a few studies have reported occasional seed-shattering plants from populations of the wild progenitor of cultivated rice (Oryza rufipogon complex) being homozygous for the putative "nonshattering" sh4 alleles.

Reproductive isolation during domestication.

It has been hypothesized that reproductive isolation should facilitate evolution under domestication. However, a systematic comparison of reproductive barrier strength between crops and their progenitors has not been conducted to test this hypothesis. Here, we present a systematic survey of reproductive barriers between 32 economically important crop species and their progenitors to better understand the role of reproductive isolation during the domestication process.

Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression.

Maize x Teosinte Hybrid Cobs Do Not Prevent Crop Gene Introgression. Whether introgression from crops to wild relatives can occur is an important component of transgene risk assessment. In the case of maize, which co-occurs with its wild relative teosinte in Mexico, the possibility of introgression has been controversial.

Rapid evolutionary divergence and ecotypic diversification of germination behavior in weedy rice populations.

Feral plants have evolved from well-studied crops, providing good systems for elucidation of how weediness evolves. As yet, they have been largely neglected for this purpose. The evolution of weediness can occur by simple back mutations in domestication genes (domestication in reverse).

Crops gone wild: evolution of weeds and invasives from domesticated ancestors.

The evolution of problematic plants, both weeds and invasives, is a topic of increasing interest. Plants that have evolved from domesticated ancestors have certain advantages for study. Because of their economic importance, domesticated plants are generally well-characterized and readily available for ecogenetic comparison with their wild descendants.

Rapid evolution of morphology and adaptive life history in the invasive California wild radish (Raphanus sativus) and the implications for management.

Understanding the evolution and demography of invasive populations may be key for successful management. In this study, we test whether or not populations of the non-native, hybrid-derived California wild radish have regionally adapted to divergent climates over their 150-year history in California and determine if population demographic dynamics might warrant different region-specific strategies for control. Using a reciprocal transplant approach, we found evidence for genetically based differences both between and among northern, coastal and southern, inland populations of wild radish.

A Pleistocene clone of Palmer's oak persisting in Southern California.

Background: The distribution of Palmer's oak (Quercus palmeri Engelm.) includes numerous isolated populations that are presumably relicts of a formerly larger range that has contracted due to spreading aridity following the end of the Pleistocene.

Principal Findings: We investigated a recently discovered disjunct population of Palmer's oak in the Jurupa Mountains of Riverside County, California.

Bidirectional history of hybridization in California wild radish, Raphanus sativus (Brassicaceae), as revealed by chloroplast DNA.

The evolutionary processes that take place in invasive plant populations are not well documented or understood. Interspecific hybridization between cultivated radish (Raphanus sativus) and R. raphanistrum is known to be responsible for the origin of the invasive California wild radish, but little is known about the nature of the hybridization events that produced the hybrid-derived lineage.

Spontaneous hybridization between maize and teosinte.

The closest wild relatives of maize, Zea mays ssp. mays are various Zea taxa known as "teosinte." Hybrids between maize and the teosinte taxon, Zea mays ssp.

Population size and relatedness affect fitness of a self-incompatible invasive plant.

One of the lingering paradoxes in invasion biology is how founder populations of an introduced species are able to overcome the limitations of small size and, in a "reversal of fortune," proliferate in a new habitat. The transition from colonist to invader is especially enigmatic for self-incompatible species, which must find a mate to reproduce. In small populations, the inability to find a mate can result in the Allee effect, a positive relationship between individual fitness and population size or density.