scholarly journals How robust is nonrandom mating in wild radish: do small pollen loads coupled with more competing pollen donors lead to random mating?

2007 ◽  
Vol 94 (2) ◽  
pp. 266-273 ◽  
Author(s):  
Marieken G. M. Shaner ◽  
Diane L. Marshall
Keyword(s):  
Random Mating ◽  
Wild Radish ◽  
Nonrandom Mating ◽  
Pollen Loads ◽  
Small Pollen

scholarly journals Predicting Rates of Inbreeding in Populations Undergoing Selection

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1851-1864 ◽  
Author(s):  
John A Woolliams ◽  
Piter Bijma
Keyword(s):  
Overlapping Generations ◽  
Linear Models ◽  
Selection Process ◽  
Correction Term ◽  
Random Mating ◽  
Nonrandom Mating ◽  
Selection Processes ◽  
Genetic Contributions ◽  
The Relationship

AbstractTractable forms of predicting rates of inbreeding (ΔF) in selected populations with general indices, nonrandom mating, and overlapping generations were developed, with the principal results assuming a period of equilibrium in the selection process. An existing theorem concerning the relationship between squared long-term genetic contributions and rates of inbreeding was extended to nonrandom mating and to overlapping generations. ΔF was shown to be ~¼(1 − ω) times the expected sum of squared lifetime contributions, where ω is the deviation from Hardy-Weinberg proportions. This relationship cannot be used for prediction since it is based upon observed quantities. Therefore, the relationship was further developed to express ΔF in terms of expected long-term contributions that are conditional on a set of selective advantages that relate the selection processes in two consecutive generations and are predictable quantities. With random mating, if selected family sizes are assumed to be independent Poisson variables then the expected long-term contribution could be substituted for the observed, providing ¼ (since ω = 0) was increased to ½. Established theory was used to provide a correction term to account for deviations from the Poisson assumptions. The equations were successfully applied, using simple linear models, to the problem of predicting ΔF with sib indices in discrete generations since previously published solutions had proved complex.

scholarly journals Pollen contamination and nonrandom mating in a Eucalyptus camaldulensis Dehnh seedling seed orchard

2016 ◽  
Vol 65 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J. M. S. Gonzaga ◽  
R. O. Manoel ◽  
A. C. B. Sousa ◽  
A. P. Souza ◽  
M. L. T. Moraes ◽  
...  
Keyword(s):  
Growth Traits ◽  
Random Mating ◽  
Management Strategies ◽  
Pollen Dispersal ◽  
Eucalyptus Camaldulensis ◽  
Paternity Analysis ◽  
Near Neighbor ◽  
Nonrandom Mating ◽  
Genetic Gains ◽  
Pollen Contamination

AbstractEucalyptus camaldulensishas potential for timber, energy, pulp and cellulose production in Brazil due to its ability to adapt to a variety of environmental conditions. The use of improved seeds, selected for economic growth traits, is necessary to increase productivity of commercial stands. Seed seedlings orchards (SSO) are one option for improved seed production. However, pollen contamination from unimproved populations, as well as non-random mating in the SSO, can decrease the predicted genetic gains in selected populations. Thus, we investigate the mating system, pollen flow and dispersal patterns in anE. camaldulensisSSO and progeny test (PT), established with seedlings collected in the SSO, using seven microsatellite loci. All trees in the SSO were mapped, sampled, and genotyped. For the PT, we sampled, genotyped, and measured the total height of seedlings from 25 families. We detected 10 % inbreeding in the PT, resulting mainly from selfing. Furthermore, we found a correlated mating rate of 18.5 % in the SSO, indicating that within the PT there are some full-sibs. Using paternity analysis, we found 14.7 % pollen contamination and a pattern of pollen dispersal between near neighbor trees in the SSO. We found 9.5 % of inbreeding depression for seedlings height. Due to pollen contamination and nonrandom mating in the SSO, the actual genetic gains for growth traits in the PT are probably lower than the predicted genetic gains. We discuss some management strategies in the SSO that can be used to increase genetic gains in commercial reforestation established using seeds collected from the SSO

Effects of pollen competition on the reproductive performance in cucurbit hybrids (Cucurbitaceae): F1 and backcross generations

1996 ◽  
Vol 74 (7) ◽  
pp. 1113-1118 ◽  
Author(s):  
Mauricio Quesada ◽  
Andrew G. Stephenson ◽  
James A. Winsor
Keyword(s):  
Reproductive Performance ◽  
Reproductive Output ◽  
Backcross Progeny ◽  
Field Studies ◽  
Field Conditions ◽  
Pollen Competition ◽  
Plant Fitness ◽  
Pollen Loads ◽  
Pollen Performance ◽  
Small Pollen

We examined the effect of pollen competition on the reproductive performance of Cucurbita F1 and backcross progeny while attempting to control for nongenetic maternal effects and nonrandom seed abortion as possible explanations for the data. We compared the vigor of F1 and backcross progeny produced from large and small pollen loads under field conditions. The results from both field studies indicated that the progeny produced from large pollen loads outperformed the progeny produced from small pollen loads for several measures of vigor. The F1 progeny produced from large pollen loads germinated faster, and produced 12% more staminate flowers and 9% more pistillate flowers than the progeny from the small pollen loads. Similarly, the backcross progeny produced from large pollen loads germinated faster, and produced 8% more pistillate flowers and 20% more fruits than the progeny from the small pollen loads. This study demonstrates a positive correlation between the size of the pollen load and the vigor of the resulting progeny under field conditions. Keywords: pollen competition, pollen performance, nonrandom fertilization, plant fitness, reproductive output.

Pseudo-Random Mating with Multiple Alleles

2021 ◽  
Vol 24 (4) ◽  
pp. 200-203
Author(s):  
Alan E. Stark
Keyword(s):  
Blood Group ◽  
Stable Equilibrium ◽  
Random Mating ◽  
Abo Blood Group ◽  
Autosomal Locus ◽  
Multiple Alleles ◽  
Nonrandom Mating

AbstractThe conditions on the mating matrix associated with a stable equilibrium are specified for an autosomal locus with four alleles. An example illustrates how Hardy–Weinberg proportions are maintained with nonrandom mating. The ABO blood group provides an illustration.

The reproductive biology of Hydrocharis morsus-ranae. I. Floral biology

1984 ◽  
Vol 62 (12) ◽  
pp. 2779-2787 ◽  
Author(s):  
Robin W. Scribailo ◽  
Usher Posluszny
Keyword(s):  
Aquatic Plant ◽  
Fruit Set ◽  
Floral Biology ◽  
Maximum Expansion ◽  
Pollen Loads ◽  
Rapid Production ◽  
Small Pollen ◽  
Male Flowers ◽  
Effective Pollinators ◽  
Insect Visitors

Hydrocharis morsus-ranae L. is a Eurasian aquatic plant introduced to North America. It spreads primarily by the rapid production and growth of stolons and overwintering turions but still flowers extensively. The white, trimerous flowers of H. morsus-ranae are emergent and unisexual, with male flowers clustered in a cyme of up to five buds and females always solitary. Both sexes of flowers, once open, last a single day, with individual male flowers opening sequentially from a given inflorescence but not necessarily on successive days. First openings in the corollas of flowers were visible by 0730 and maximum expansion was usually reached by late morning. Anthers dehisce and stigmas become receptive by 0930 with both reaching maxima by midday. The flowers produce a sweet nectar and scent which attract, and are easily accessible to, a wide variety of insects visiting the open bowl-shaped flowers. The most abundant insect visitors to the flowers were Homoptcra (Aphididae) and Hydrellia and Notiphila spp. (Diptera: Ephydridae). Both groups were found to carry small pollen loads and because of their erratic anthophilous behaviour were not considered important in pollination. Although fewer in number, the more specialized hover flies, Toxomerus marginatus (Say) (Diptera: Syrphidae), and solitary bees, Dialictus sp. (Hymcnoptera: Halictidae), were considered more likely to be the primary pollinators. After pollination and the day after anthesis, female flowers are drawn underwater by pedical recurvation and 4–6 weeks later mature into globose berrylike fruits. Fruit-sets were 38.3% in naturally pollinated flowers, 96.5% in bagging experiments with hand-pollinations, and absent in bagging experiments for agamospermy with unopened flowers. These results substantiated that poor fruit-set in some populations was caused by a lack of effective pollinators. Seed densities of 250/m2 were still estimated with the above data.

scholarly journals Sex-biased admixture and assortative mating shape genetic variation and influence demographic inference in admixed Cabo Verdeans

2020 ◽  
Author(s):  
Katharine L Korunes ◽  
Giordano Bruno Soares-Souza ◽  
Katherine Bobrek ◽  
Hua Tang ◽  
Isabel Inês Araújo ◽  
...  
Keyword(s):  
Genetic Variation ◽  
African Ancestry ◽  
Random Mating ◽  
Historical Record ◽  
Genomic Variation ◽  
Population History ◽  
Specific Gene ◽  
Nonrandom Mating ◽  
Cabo Verde ◽  
Demographic Inference

Genetic data can provide insights into population history, but first we must understand the patterns that complex histories leave in genomes. Here, we consider the admixed human population of Cabo Verde to understand the patterns of genetic variation left by social and demographic processes. First settled in the late 1400s, Cabo Verdeans are admixed descendants of Portuguese colonizers and enslaved West African people. We consider Cabo Verde′s well-studied historical record alongside genome-wide SNP data from 563 individuals from 4 regions within the archipelago. We use genetic ancestry to test for patterns of nonrandom mating and sex-specific gene flow, and we examine the consequences of these processes for common demographic inference methods and for genetic patterns. Notably, multiple population genetic tools that assume random mating underestimate the timing of admixture, but incorporating non-random mating produces estimates more consistent with historical records. We consider how admixture interrupts common summaries of genomic variation such as runs-of-homozygosity (ROH). While summaries of ROH may be difficult to interpret in admixed populations, differentiating ROH by length class shows that ROH reflect historical differences between the islands in their contributions from the source populations and post-admixture population dynamics. Finally, we find higher African ancestry on the X chromosome than on the autosomes, consistent with an excess of European males and African females contributing to the gene pool. Considering these genomic insights into population history in the context of Cabo Verde′s historical record, we can identify how assumptions in genetic models impact inference of population history more broadly.

scholarly journals Pseudo-random mating populations. In celebration of the 80th anniversary of the Hardy-Weinberg law.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 731-737
Author(s):  
C C Li
Keyword(s):  
Random Mating ◽  
Sufficient Condition ◽  
Autosomal Locus ◽  
Multiple Alleles ◽  
Nonrandom Mating ◽  
80Th Anniversary ◽  
Basic Case ◽  
Offspring Generation

Abstract That random mating leads to Hardy-Weinberg distribution of genotypes is well known. This report is to show that, if the deviations from random mating are of a certain pattern, the offspring generation will also be in Hardy-Weinberg proportions. This brings out the fact that random mating is a sufficient condition, not a necessary one, for the attainment of the Hardy-Weinberg proportions. Such nonrandom-mating populations are tentatively said to be pseudo-random mating. Pseudo-random-mating populations exist for both autosomal and sex-linked systems with two or multiple alleles. This report covers the basic case of a two-allele autosomal locus in detail, but the possible extension to two loci and cytonuclear systems have also been mentioned in discussion.

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