scholarly journals Balanced Polymorphisms With Unlinked Loci

1963 ◽  
Vol 16 (1) ◽  
pp. 1 ◽  
Author(s):  
PAP Moran
Keyword(s):  
Stationary States ◽  
Genetic Population ◽  
Degenerate Cases

The stationary states of a genetic population whose fitness is controlled by two independent loci, with two alleles each, are considered. It is shown that apart from degenerate cases there are at most five such states. It is also shown that there are at most three stationary states which are stable. Examples are given where these bounds are attained.

Global stability of genetic systems governed by mutation and selection. II

1977 ◽  
Vol 81 (3) ◽  
pp. 435-441 ◽  
Author(s):  
P. A. P. Moran
Keyword(s):  
Global Stability ◽  
Evolutionary Theory ◽  
Infinite Number ◽  
Infinite Sequence ◽  
Stable State ◽  
Single Locus ◽  
Stationary States ◽  
Genetic Population ◽  
Nearest Neighbours ◽  
Mutation And Selection

AbstractAn infinite genetic population of haploid particles is considered in which selection is controlled by a single locus at which there are an infinite number of possible alleles. These alleles are arranged in an infinite sequence and mutation occurs only to nearest neighbours. This is the ‘ladder model’ of Ohta and Kimura which was put forward as a possible explanation of the distributions of electromorphs in electrophoretic observations. Following an earlier paper, conditions are obtained on the selection coefficients which ensure that a stationary stable state exists. One such model is solved explicitly. The problem, important in evolutionary theory, of the rate of approach to such stationary states starting from some other state, is also discussed briefly.

Genetic Population Diversity of Aedes caspius in Southern Provinces of Iran

2018 ◽  
Vol 111 (1) ◽  
pp. 31-37 ◽  
Author(s):  
S DOOSTI ◽  
MR YAGHOOBI-ERSHADI ◽  
MM SEDAGHAT ◽  
SH MOOSA-KAZEMI ◽  
K AKBARZADEH ◽  
...  
Keyword(s):  
Population Diversity ◽  
Genetic Population ◽  
Aedes Caspius

scholarly journals Some Remarks on the Regular Splitting of Quasi-Polynomials with Two Delays. Characterization of Double Roots in Degenerate Cases

2020 ◽  
Vol 53 (2) ◽  
pp. 4386-4391
Author(s):  
Alejandro Martínez-González ◽  
César-Fernando Méndez-Barrios ◽  
Silviu-Iulian Niculescu
Keyword(s):  
Regular Splitting ◽  
Two Delays ◽  
Degenerate Cases

scholarly journals Production performance of cows raised with different post-weaning growth patterns

2021 ◽  
Author(s):  
Harvey C Freetly ◽  
Robert A Cushman ◽  
Gary L Bennett
Keyword(s):  
Growth Pattern ◽  
Bos Taurus ◽  
Life Time ◽  
Growth Patterns ◽  
Production Performance ◽  
Genetic Population ◽  
Breed Type ◽  
Genetic Types ◽  
Period 2 ◽  
Step Growth

Abstract The period of heifer development is a relatively small fraction of a cow’s life; however, her pattern of growth may have permanent effects on her productivity as a cow. We hypothesized that altering the growth pattern during the peri-pubertal period would increase life-time productivity across genetic types of Bos taurus cows. The objective was to determine the stayability, calf production, and weight of calf weaned across six calf crops. Heifers (n = 685) were placed on one of two developmental programs at 256 ± 1 d of age. Control heifers received a diet that provided 228 kcal ME·(BW, kg) -0.75 daily, and Stair-Step heifers were allocated 157 kcal ME·(BW, kg) -0.75 daily for 84 or 85 d, and then the daily allocation was increased to 277 kcal ME·(BW, kg) -0.75. Stair-Step heifers (0.33 ± 0.02 kg/d) had a lower ADG than Control heifers (0.78 ± 0.02 kg/d; P < 0.001) during Period 1, and Stair-Step heifers (0.93 ± 0.03 kg/d) had a greater ADG than Controls (0.70 ± 0.03 kg/d; P < 0.001) during Period 2. There were no treatment (P = 0.28) or breed type differences (P = 0.42) for the proportion of cows weaning a calf; however, the proportion of cows weaning a calf decreased with cow age (P < 0.001). Calves from Stair-Step dams had heavier weaning weights (193 ± 1 kg) compared to Control calves (191 ± 1 kg; P = 0.007). There was not a treatment (P = 0.25) or breed type differences in cumulative BW weaned (P = 0.59). A diverse genetic population of cattle within Bos taurus was tested and responses in calf production did not differ between Stair-Step growth pattern and a more constant non-obese growth pattern.

Determination of catastrophic sets of a tubular chemical reactor by two-parameter continuation method

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Marek Berezowski
Keyword(s):  
Continuation Method ◽  
Extreme Points ◽  
Chemical Reactor ◽  
Stationary States ◽  
Parameter Continuation Method ◽  
It Systems ◽  
Parametric Continuation ◽  
Parameter Continuation ◽  
Two Parameter

AbstractThe work relates to development and presentation a two-parameter continuation method for determining catastrophic sets of stationary states of a tubular chemical reactor with mass recycle. The catastrophic set is a set of extreme points occurring in the bifurcation diagrams of the reactor. There are many large IT systems that use the parametric continuation method. The most popular is AUTO’97. However, its use is sometimes not convenient. The method developed in this work allows to eliminate the necessity to use huge IT systems from the calculations. Unlike these systems, it can be inserted into the program as a short subroutine. In addition, this method eliminates time-consuming iterations from the calculations.

scholarly journals Genetic population structure of the monogenean parasite Gyrodactylus thymalli and its host European grayling (Thymallus thymallus) in a large Norwegian lake

Hydrobiologia ◽  
2020 ◽  
Author(s):  
Ruben Alexander Pettersen ◽  
Claudia Junge ◽  
Kjartan Østbye ◽  
Tor Atle Mo ◽  
Leif Asbjørn Vøllestad
Keyword(s):  
Genetic Structure ◽  
Evolutionary Biology ◽  
Isolation By Distance ◽  
Genetic Structuring ◽  
Thymallus Thymallus ◽  
Homing Behavior ◽  
Genetic Population ◽  
Monogenean Parasite ◽  
European Grayling ◽  
Genetic Clusters

Abstract Understanding how populations are structured in space and time is a central question in evolutionary biology. Parasites and their hosts are assumed to evolve together, however, detailed understanding of mechanisms leading to genetic structuring of parasites and their hosts are lacking. As a parasite depends on its host, studying the genetic structure of both parasite and host can reveal important insights into these mechanisms. Here, genetic structure of the monogenean parasite Gyrodactylus thymalli and its host the European grayling (Thymallus thymallus) was investigated in 10 tributaries draining into the large Lake Mjøsa in Norway. The population genetic structure of spawning grayling was studied using microsatellite genotyping, while G. thymalli was studied by sequencing a mitochondrial DNA gene (dehydrogenase subunit 5). Two main genetic clusters were revealed in grayling, one cluster comprising grayling from the largest spawning population, while the remaining tributaries formed the second cluster. For both taxa, some genetic differentiation was observed among tributaries, but there was no clear isolation-by-distance signature. The structuring was stronger for the host than for the parasite. These results imply that moderate to high levels of gene flow occur among the sub-populations of both taxa. The high parasite exchange among tributaries could result from a lack of strong homing behavior in grayling as well as interactions among individual fish outside of the spawning season, leading to frequent mixing of both host and parasite.

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