The structure and dynamics of a hybrid population of Anigozanthos manglesii D. Don and A. humilis Lindl. (Haemodoraceae)

1977 ◽  
Vol 25 (4) ◽  
pp. 413 ◽  
Author(s):  
SD Hopper

The structure of a hybrid kangaroo paw population (Anigozanthos Labill.) in the shire cemetery at Gingin, Western Australia, was analysed from multivariate morphometric, pollen fertility and floral colour data. A. manglesii D. Don. comprised 87% of the population of 9547 flowering individuals in 1976, and occupied the lower, wetter areas of the cemetery to the exclusion of A. humilis Lindl. A. humilis (11 % of the population) occurred at the greatest density on the higher, drier areas. The intervening ecotonal regions were occupied by both species, and by the majority of F1 hybrids (0.5 % of the population) and backcrosses (c. 2%). Census data documented a threefold increase in the number of A. manglesii individuals, a slight increase in the number of F1 hybrids, and a decrease in the number of A. humilis by a third over a 3-year study period. These data suggest the occurrence of a limited amount of introgressive gene exchange in the face of potent barriers to interspecific hybridization.

1978 ◽  
Vol 26 (3) ◽  
pp. 309 ◽  
Author(s):  
SD Hopper

The floral morphology and pollen fertility of progeny from open-pollinated plants in a hybrid population of A. manglesii and A. humilis were measured to investigate patterns of gene exchange occurring between hybrid and parental individuals. Introgression occurs where the two species and F1 hybrids grow in close proximity in the population but the possibility of more backcrossing to A. manglesii than to A. humilis remains an open question on present evidence. The morphological effects of hybridization became cryptic in some cases within one and in most cases within two generations of backcrossing. The possible evolutionary significance of natural hybridization between A. manglesii and A. humilis is discussed in the light of these results.


Author(s):  
O. V. Gladysheva ◽  
Т. А. Barkovskaya

This article presents the results of a study of hybrid spring wheat populations. Revealed different patterns of inheritance of important traits in F1 hybrids, which is caused by hereditary features of the original forms and circumstances. Analysis of hybrid populations showed that the dominant role in the formation of 1000 grains mass belongs to productivity and weight of grain with an ear, correlation coefficient r = 0.90 and amounted to r = 0.73, respectively. Found that the hybrid population in F4-5, created on the basis of grades Moscow 35, Esther, Agatha, Rome, Saratovskaya 29 (Russia), Ostinka (Ukraine) are a valuable material for selection of highly productive genotypes for future use breeding process. 


2020 ◽  
pp. 107808742092590
Author(s):  
David J. Amaral

Despite cross-disciplinary attention to laws targeting homeless behavior in cities, systematic analysis of the power dynamics behind the adoption and implementation of such laws is surprisingly scarce. This article addresses that oversight by investigating the politics of anti-homeless policies in San Francisco, a critical and revealing case. Using a mixed-methods approach that joins qualitative analysis of public records with spatial and statistical analysis of precinct-level election results, census data, and geocoded police and 311 records, it evaluates previously unmeasured claims concerning the relative influence of social and economic forces in determining policy adoption and assesses whether enforcement patterns betray preferential treatment. Findings suggest that in the face of mobilized opposition, an anti-homeless regime composed of business and neighborhood merchants, elected officials, conservatives, and homeowners each contribute resources required to pass anti-homeless laws. Contrary to past claims, enforcement practices do not appear to privilege only the downtown business district.


2018 ◽  
Author(s):  
Daniel Oreperk ◽  
Sarah A Schoenrock ◽  
Rachel McMullan ◽  
Robin Ervin ◽  
Joseph Farrington ◽  
...  

ABSTRACTParent-of-origin effects (POEs) in mammals typically arise from maternal effects or from imprinting. Mutations in imprinted genes have been associated with psychiatric disorders, as well as with changes in a handful of animal behaviors. Nonetheless, POEs on complex traits such as behavior remain largely uncharacterized. Furthermore, although perinatal environmental exposures, such as nutrient deficiency, are known to modify both behavior and epigenetic effects generally, the architecture of environment-by-POE is almost completely unexplored. To study POE and environment-by-POE, we employ a relatively neglected but maximally powerful POE-detection system: a reciprocal F1 hybrid population. We exposed female NOD/ShiLtJxC57Bl/6J and C57Bl/6JxNOD/ShiLtJ mice, in utero, to one of four different diets, then after weaning recorded their whole-brain gene expression, as well as a set of behaviors that model psychiatric disease. Microarray expression data revealed an imprinting-enriched set of over a dozen genes subject to POE; the POE on the most significantly affected gene, Carmil1 (a.k.a. Lrrc16a), was validated using qPCR in the same and in a new set of mice. Several behaviors, especially locomotor behaviors, also showed POE. Interestingly, Bayesian mediation analysis suggests Carmil1 expression suppresses behavioral POE, and Airn suppresses POE on Carmil1 expression. A significant diet-by-POE was observed on one behavior, one imprinted gene, and over a dozen non-imprinted genes. Beyond our particular results, our study demonstrates a reciprocal F1 hybrid framework for studying POE and environment-by-POE on behavior.


1969 ◽  
Vol 20 (2) ◽  
pp. 227 ◽  
Author(s):  
KS McWhirter

A type of male sterility found in two Desmodium plants of probably interspecific hybrid origin was cytoplasmically inherited. The cytoplasmic male-sterile character was incorporated in the tropical legume Desmodium sandwicense by backcrossing. In this genetic background pollen sterility was complete. The male-sterile character was not graft-transmissible, and it produced no detectable pleiotropic effects on growth and development. Desmodium intortum gave restoration of pollen fertility in Fl hybrids with male-sterile lines of D. sandwicense. Restored F1 hybrids produced apparently normal pollen, but tests of functional ability of the pollen disclosed that pollen fertility was less than that of Fl hybrids with normal cytoplasm. Incomplete restoration of fertility was not due to heterozygosity of fertility-restoring genes with gametophytic expression, since fertility-restoring genes were shown to act sporophytically. The results established the occurrence in the legume Desmodium of a system of determination of the male-sterile, fertility-restored phenotypes that is similar to the cytoplasmic male sterility systems described in many other angiosperm plants. A scheme utilizing the genetic stocks produced in this study for commercial production of the interspecific hybrid D. sandwicense x D. intortum as a cultivar is presented.


Hereditas ◽  
2008 ◽  
Vol 112 (3) ◽  
pp. 221-230 ◽  
Author(s):  
ARJA OJALA ◽  
ARNE ROUSI ◽  
EVA LEWING ◽  
HEIKKI PYYSALO ◽  
CARL-JOHAN WIDÉN

2012 ◽  
Vol 16 (6) ◽  
pp. 417-423 ◽  
Author(s):  
Paul Kuzel ◽  
Andrei I. Metelitsa ◽  
Douglas C. Dover ◽  
Thomas G. Salopek

Background: The epidemiology of sebaceous carcinoma (SC) has not previously been examined in a Canadian population. Objective: To determine the epidemiologic trends of SC in Alberta, Canada, from 1988 to 2007. Methods: This study was a population-based, retrospective, epidemiologic analysis of SC in Alberta over a 20-year span. Results: Over the study period, the age-standardized SC incidence increased from 0.22 per 100,000 to 0.65 per 100,000. Sebaceous carcinoma is a cancer that predominantly affects the elderly (over 85% of cases were in persons 60 years or older). Interestingly, the face (37.7% of cases), not the eyelids (26.2% of cases), was the most frequently affected site overall. Gender-specific trends reflected a slight male predominance (1.4:1) and significant differences in anatomic distribution between the sexes. Conclusion: For unexplained reasons, there has been a threefold increase in SC incidence in Alberta over the last two decades. In addition, there are significant gender-specific differences in the anatomic distribution of SC. Contexte: L'épidémiologie du carcinome sébacé (CS) n'a jamais fait l'objet d'étude au Canada. Objectif: L'étude visait à déterminer les tendances épidémiologiques du CS en Alberta, au Canada, de 1988 à 2007. Méthodes: Il s'agit d'une analyse épidémiologique, rétrospective, fondée sur la population, du CS, en Alberta, sur une période de 20 ans. Résultats: Au cours de la période à l'étude, l'incidence du CS normalisée selon l'âge est passée de 0.22 pour 100,000 à 0.65 pour 100,000. Le carcinome sébacé est un cancer qui touche surtout les personnes âgées (plus de 85% des cas se comptaient parmi les personnes de 60 ans et plus). Point intéressant, la région le plus souvent touchée, dans l'ensemble, était la face (37.7% des cas), et non les paupières (26.2% des cas). Les tendances propres à chaque sexe ont révélé une fréquence légèrement plus élevée chez les hommes que chez les femmes (1.4/1) et des différences importantes entre les sexes quant à la répartition anatomique du siège des lésions. Conclusion: Pour des raisons inconnues, l'incidence du CS a triplé en Alberta au cours des deux dernières décennies. De plus, il existe des différences importantes entre les sexes quant à la répartition anatomique du CS.


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