General and Exact Inbreeding Coefficient of Maize Synthetics Derived from Three-Way Line Hybrids

Inbreeding is reduced and genetic diversity enhanced when a small isolated inbred population is crossed to another unrelated population. Crossing can have beneficial or harmful effects on fitness, but beneficial effects predominate, and the risks of harmful ones (outbreeding depression) can be predicted and avoided. For crosses with a low risk of outbreeding depression, there are large and consistent benefits on fitness that persist across generations in outbreeding species. Benefits are greater in species that naturally outbreed than those that inbreed, and increase with the difference in inbreeding coefficient between crossed and inbred populations in mothers and zygotes. However, benefits are similar across invertebrates, vertebrates and plants. There are also important benefits for evolutionary potential of crossing between populations.

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Allozyme variation and an estimate of the inbreeding coefficient in the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae)

Bulletin of Entomological Research ◽

10.1017/s000748530005197x ◽

1995 ◽

Vol 85 (1) ◽

pp. 21-28 ◽

Cited By ~ 9

Author(s):

Philippe Borsa ◽

D. Pierre Gingerich

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Population Genetic ◽

New Caledonia ◽

Allozyme Variation ◽

Inbreeding Coefficient ◽

Hypothenemus Hampei ◽

Coffee Berry ◽

Biological Features ◽

High Degree

AbstractSeven presumed Mendelian enzyme loci (Est-2, Est-3, Gpi, Idh-l, Idh-2, Mdh-2 and Mpi) were characterized and tested for polymorphism in coffee berry borers, Hypothenemus hampei (Ferrari), sampled in Côte d′Ivoire, Mexico and New Caledonia. The average genetic diversity was H = 0.080. Two loci, Mdh-2 and Mpi were polymorphic, and thus usable as genetic markers. The population structure of H. hampei was analysed using Weir & Cockerham's estimators of Wright's F-statistics. A high degree of inbreeding (f = 0.298) characterized the elementary geographic sampling unit, the coffee field. The estimate of gene flow between fields within a country was Nm = 10.6 and that between countries was Nm = 2. The population genetic structure in H. hampei could be related to its known population biological features and history.

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Evidence for a quantitative genetic influence on the formation of aortic valves with two leaflets in the Syrian hamster

Cardiology in the Young ◽

10.1017/s1047951100001396 ◽

1993 ◽

Vol 3 (2) ◽

pp. 132-140 ◽

Cited By ~ 18

Author(s):

Valentín Sans-Coma ◽

Manuel Cardo ◽

Ana C. Durán ◽

Diego Franco ◽

Borja Fernández ◽

...

Keyword(s):

Aortic Valve ◽

Inbreeding Coefficient ◽

Quantitative Inheritance ◽

Histologic Study ◽

Aortic Valves ◽

Aortic Sinus ◽

Quantitative Genetic ◽

Corrosion Cast ◽

The Right ◽

Cast Technique

SummaryWe studied the morphology of the aortic valves of 1,036 Syrian hamsters belonging to two families subjected to high endogamous pressure. Most (n=955) specimens were examined using a corrosion-cast technique. In the remaining 81 specimens, valvar morphology was assessed by means of a stereomicroscope, and in 18 of these cases a histologic study was also performed. In one of the families, a high proportion (30.5%) of hamsters had aortic valves with two leaflets, the aortic sinuses being oriented ventrodorsally. The percentage of such anomalous valves was found to be positively correlated with the inbreeding coefficient of specimens. In the other family, the occurrence of an aortic valve with two leaflets was a sporadic event. Stereoscopic and histologic observations demonstrated that, in 52 of 63 aortic valves with three leaflets, the ventral commissure between the right and left leaflets was partially fused, while in 10 other cases this commissure was completely fused. In addition, in nine of 18 aortic valves with two leaflets, there was a more or less well-developed raphe located in the ventral aortic sinus, approximately where the true ventral commissure would have been. Our observations suggest the existence of a continuous spectrum of aortic valvar morphology, ranging from a valve with three leaflets and no fusion of the ventral commissure to an aortic valve with two leaflets devoid of any raphe. This spectrum seems to be the result of the interaction of genetic and intrauterine environmental factors. Results of crosses between both related and unrelated hamsters suggest that the observed morphology in individuals is the result of quantitative inheritance.

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Effect of inbreeding and individual increase in inbreeding on growth in Nilagiri and Sandyno breeds of sheep

Animal Genetic Resources/Ressources génétiques animales/Recursos genéticos animales ◽

10.1017/s2078633615000338 ◽

2016 ◽

Vol 58 ◽

pp. 63-71 ◽

Cited By ~ 1

Author(s):

R. Venkataramanan ◽

A. Subramanian ◽

S.N. Sivaselvam ◽

T. Sivakumar ◽

C. Sreekumar ◽

...

Keyword(s):

Growth Traits ◽

Inbreeding Coefficient ◽

Pedigree Information ◽

Research Station ◽

Sheep Breeding ◽

Inbreeding Coefficients ◽

Equivalent Number ◽

Breeding Research ◽

Percent Increase ◽

Two Populations

SummaryIndividual increase in inbreeding coefficients (ΔFi) has been recommended as an alternate measure of inbreeding. It can account for the differences in pedigree knowledge of individual animals and avoids overestimation due to increased number of known generations. The effect of inbreeding (F) and equivalent inbreeding (EF) calculated fromΔFi, on growth traits were studied in Nilagiri and Sandyno flocks of sheep. The study was based on data maintained at the Sheep Breeding Research Station, Sandynallah. The pedigree information and equivalent number of generations were less in Sandyno compared with Nilagiri sheep. The average F and EF for the Nilagiri population were 2.17 and 2.44, respectively and the corresponding values for Sandyno sheep were 0.83 and 0.84, respectively. The trend of inbreeding over years in both the populations indicated that EF was higher during earlier generations when pedigree information was shallow. Among the significant effects of inbreeding, the depression in growth per 1 percent increase in inbreeding ranged from 0.04 kg in weaning weight to 0.10 kg in yearling weight. In general, more traits were affected by inbreeding in Nilagiri sheep, in which greater regression of growth traits was noticed with F compared with EF. Higher values of EF than F in earlier generations in both the populations indicate that EF avoided the potential overestimation of inbreeding coefficient during recent generations. In the Sandyno population, the magnitude of depression noticed among growth traits with significant effects of inbreeding was higher. The differences in response to F and EF noticed in the two populations and possible causes for the trait wise differences in response to F and EF are appropriately discussed.

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Population structure of Czech cold-blooded breeds of horses

Archives Animal Breeding ◽

10.5194/aab-54-1-2011 ◽

2011 ◽

Vol 54 (1) ◽

pp. 1-9

Author(s):

L. Vostrý ◽

Z. Čapková ◽

J. Přibyl ◽

B. Hofmanová ◽

H. Vostrá Vydrová ◽

...

Keyword(s):

Population Structure ◽

Genetic Variability ◽

Population Size ◽

Effective Population Size ◽

Inbreeding Coefficient ◽

Effective Population ◽

The Czech Republic ◽

Generation Interval ◽

Average Value ◽

Inbreeding Coefficients

Abstract. In order to estimate effective population size, generation interval and the development of inbreeding coefficients (Fx) in three original breeds of cold-blooded horses kept in the Czech Republic: Silesian Noriker (SN), Noriker (N) and Czech-Moravian Belgian horse (CMB) all animals of the particular breeds born from 1990 to 2007 were analysed. The average values of generation interval between parents and their offspring were: 8.53 in SN, 8.88 in N and 8.56 in CMB. Average values of effective population size were estimated to be: 86.3 in SN, 162.3 in N and 104.4 in CMB. The average values of inbreeding coefficient were 3.13 % in SN stallions and 3.39 % in SN mares, in the N breed 1.76 % and 1.26 % and in the CMB breed 3.84 % and 3.26 % respectively. Overall averages of Fx were: 3.23 %, 1.51 % and 3.55 % for the breeds SN, N and CMB. The average value of inbreeding coefficient Fx increased by 1.22 % in SN, by 0.35 % in N and by 1.01 % in CMB, respectively. This may lead to a reduction in genetic variability. Reduction in genetic variability could be either controlled in cooperation with corresponding populations of cold-blooded breeds in other European countries or controlled by number of sires used in population

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IDENTITY COEFFICIENTS IN FINITE POPULATIONS. I. EVOLUTION OF IDENTITY COEFFICIENTS IN A RANDOM MATING DIPLOID DIOECIOUS POPULATION

Genetics ◽

10.1093/genetics/86.3.697 ◽

1977 ◽

Vol 86 (3) ◽

pp. 697-713

Author(s):

C Chevalet ◽

M Gillois ◽

R F Nassar

Keyword(s):

Genetic Variability ◽

Population Size ◽

Effective Population Size ◽

Random Mating ◽

Matrix Multiplication ◽

Inbred Lines ◽

Inbreeding Coefficient ◽

Effective Population ◽

The Mean ◽

Over Time

ABSTRACT Properties of identity relation between genes are discussed, and a derivation of recurrent equations of identity coefficients in a random mating, diploid dioecious population is presented. Computations are run by repeated matrix multiplication. Results show that for effective population size (Ne) larger than 16 and no mutation, a given identity coefficient at any time t can be expressed approximately as a function of (1—f), (1—f)3 and (1—f)6, where f is the mean inbreeding coefficient at time t. Tables are presented, for small Ne values and extreme sex ratios, showing the pattern of change in the identity coefficients over time. The pattern of evolution of identity coefficients is also presented and discussed with respect to N eu, where u is the mutation rate. Applications of these results to the evolution of genetic variability within and between inbred lines are discussed.

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Effects of inbreeding on number of piglets born total, born alive and weaned in Austrian Large White and Landrace pigs

Archives Animal Breeding ◽

10.5194/aab-52-51-2009 ◽

2009 ◽

Vol 52 (1) ◽

pp. 51-64 ◽

Cited By ~ 2

Author(s):

A. Köck ◽

B. Fürst-Waltl ◽

R. Baumung

Keyword(s):

Inbreeding Depression ◽

Reproductive Performance ◽

Regression Models ◽

Inbreeding Coefficient ◽

Significant Positive Effect ◽

Weaned Piglets ◽

Large White ◽

Inbreeding Coefficients ◽

Negative Effect ◽

Positive Effect

Abstract. In this study records of 58 925 litters of Austrian Large White and 17 846 litters of Austrian Landrace pigs were analysed. Regression models were used to determine the effects of litter, dam and sire inbreeding on total number of born, born alive and weaned piglets in Large White and Landrace. In both populations, litter and dam inbreeding showed a negative effect on all traits. Sire inbreeding had no effect in Large White, whereas a significant positive effect was observed in Landrace. On average, inbred sires with an inbreeding coefficient of 10 % had 0.45 more piglets born total and 0.43 more piglets born alive in comparison to non-inbred sires. In a further analysis the total inbreeding coefficients of the animals were divided into two parts: »new« and »old« inbreeding. »New« inbreeding was defined as the period of the first five generations. It was shown that the observed inbreeding effects were not only caused by recent inbreeding. Reproductive performance was also affected by »old« inbreeding. Finally partial inbreeding coefficients of four important ancestors in each population were calculated to investigate if inbreeding effects are similar among these ancestors. The results revealed a varation of inbreeding effects among the four ancestors. Alleles contibuting to inbreeding depression were descendent from specific ancestors.

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Heterozygosity but not inbreeding coefficient predicts parasite burdens in the banded mongoose

Journal of Zoology ◽

10.1111/jzo.12424 ◽

2016 ◽

Vol 302 (1) ◽

pp. 32-39 ◽

Cited By ~ 6

Author(s):

J. Mitchell ◽

E. I. K. Vitikainen ◽

D. A. Wells ◽

M. A. Cant ◽

H. J. Nichols

Keyword(s):

Inbreeding Coefficient ◽

Banded Mongoose

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