scholarly journals Study of a Turkey Population for Gene Preservation

2004 ◽  
pp. 48-52
Author(s):  
Szilvia Szőke ◽  
István Komlósi ◽  
Edit Korom ◽  
Márton Ispány ◽  
Sándor Mihók
Keyword(s):  
Information Theory ◽  
Genetic Variability ◽  
Genetic Variance ◽  
Rotational Line ◽  
Small Populations ◽  
Gene Conservation ◽  
Selection Methods ◽  
Breeding Method ◽  
Present Generation ◽  
Additional Protection

Genetic variability is very important in small populations. We examined an indigenous bronze turkey population which is bred for gene conservation in order to see if the current mating system maintains genetic variability. The present generation was surveyed using microsatellite markers and a computer model was used to simulate changes in the population over 100 generations.The data was analysed using the concept of entrophy from information theory instead of genetic variance so that we could more accurately measure genetic variability.The results indicate that the breeding method currently in use, rotational line mating, is acceptable with respect to preserving genetic variability, but new selection methods may provide additional protection against the loss of alleles.

scholarly journals A statistical analysis of population variability in Bronze Turkey considering gene conservation

2004 ◽  
Vol 47 (4) ◽  
pp. 377-385
Author(s):  
S. Szőke ◽  
I. Komlósi ◽  
E. Korom ◽  
M. Ispány ◽  
S. Mihók
Keyword(s):  
Information Theory ◽  
Genetic Variability ◽  
Genetic Variance ◽  
Rotational Line ◽  
Small Populations ◽  
Gene Conservation ◽  
Selection Methods ◽  
Breeding Method ◽  
Present Generation ◽  
Additional Protection

Abstract. Genetic variability is very important in small populations. We examined an indigenous Bronze Turkey population which is bred for gene conservation in order to see if the current mating system maintains genetic variability. The present generation was surveyed using microsatellite markers and a computer model was used to simulate changes in the population over 100 generations. The data was analysed using the concept of entrophy from information theory instead of genetic variance so that we could measure genetic variability more accurately. The results indicate that the breeding method currently in use, rotational line mating, is acceptable with respect to preserving genetic variability, but new selection methods may provide additional protection against the loss of alleles.

scholarly journals Pedigree Analysis of Mangalica Pig Breeds

2016 ◽  
Vol 16 (3) ◽  
pp. 701-709 ◽  
Author(s):  
János Posta ◽  
Péter Szabó ◽  
István Komlósi
Keyword(s):  
Genetic Structure ◽  
Genetic Variability ◽  
Gene Pool ◽  
Reference Population ◽  
Pedigree Analysis ◽  
Small Populations ◽  
Gene Conservation ◽  
Generation Interval ◽  
Pig Breeds ◽  
Gene Origin

AbstractAn effective gene conservation programme requires the knowledge of genetic variability of the population. The genetic structure of Mangalica pig breeds (Blonde, Red and Swallow-bellied) was studied from pedigree records. Herdbook data available up to 2011 of registered Mangalica pig breeds (Blonde, Red and Swallow-bellied) were analysed. The number of complete generations was 6 for Blonde and 5 for Red and Swallow-bellied Mangalica whereas the average complete generation equivalent was between 3.51 and 6.01. The average level of inbreeding of the reference population was low (4.07–5.87%). The investigated breeds could be considered as small populations based on the probability of gene origin. The most important ancestor contributed between 9 and 16% of the gene pool of the reference populations. The longest generation interval was found for the sire-to-son pathways whereas the shortest for dam-to-daughter pathways for each breed.

scholarly journals Components of genetic variability and heritability of grain yield of silage maize

Genetika ◽  
2004 ◽  
Vol 36 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Mile Secanski ◽  
Tomislav Zivanovic ◽  
Goran Todorovic ◽  
Gordana Surlan-Momirovic
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Genetic Variance ◽  
Block Design ◽  
Inbred Lines ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Silage Maize ◽  
V Genes ◽  
Set Up

The aim of the present study was to evaluate the following parameters for the grain yield of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of the diallel set. The two-year four-replicate trial was set up according to the randomized complete-block design at Zemun Polje. It was determined that a genotype, year and their interaction significantly affected variability of this trait. The highest. i.e. the lowest grain yield, on the average for both investigation years. was recorded in the silage maize inbred lines ZPLB402 and ZPLB405. respectively. The analysis of components of genetic variance for grain yield shows that the additive component (D) was lower than the dominant (H1 and H2) genetic variance, while a positive component F and the frequency of dominant (u) and recessive (v) genes for this observed trait point to prevalence of dominant genes over recessive ones. Furthermore. this is confirmed by the ratio of dominant to recessive genes in parental genotypes for grain yield (Kd/Kr> 1) that is greater than unity in both years of investigation. The estimated value of the average degree of dominance (H1/D)1/2 exceeds unity, pointing out to superdominance in inheritance of this trait in both years of investigation. Results of Vr/Vr regression analysis indicate superdominance in inheritance of grain yield. Moreover. a registered presence of non-allelic interaction points out to the need to study effects of epistasis, as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high values of broad-sense heritability for grain yield in both investigation years (98.71%, i.e. 97.19% in 1997, i.e. 1998, respectively). and low values of narrow-sense heritability (11.9% in 1997 and 12.2% in 1998).

scholarly journals Gene conservation of six Hungarian local chicken breeds maintained in small populations over time

PLoS ONE ◽  
2020 ◽  
Vol 15 (9) ◽  
pp. e0238849
Author(s):  
Nora Palinkas-Bodzsar ◽  
Nikoletta Sztan ◽  
Tamas Molnar ◽  
Andras Hidas
Keyword(s):  
Small Populations ◽  
Gene Conservation ◽  
Chicken Breeds ◽  
Local Chicken ◽  
Over Time

Low genetic variability in small populations of New Zealand kokako Callaeas cinerea wilsoni

2000 ◽  
Vol 96 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Q.J. Hudson ◽  
R.J. Wilkins ◽  
J.R. Waas ◽  
I.D. Hogg
Keyword(s):  
New Zealand ◽  
Genetic Variability ◽  
Small Populations

Genetic variance of early height growth and expected gains from selection in a Minnesota population of black spruce

1991 ◽  
Vol 21 (1) ◽  
pp. 11-19 ◽  
Author(s):  
C. Dana Nelson ◽  
Carl A. Mohn
Keyword(s):  
Genetic Variance ◽  
Black Spruce ◽  
Local Population ◽  
Index Selection ◽  
Phenotypic Variance ◽  
Minimal Risk ◽  
Individual Selection ◽  
Selection Methods ◽  
Improvement Project ◽  
Seed Orchards

A genetic improvement project for black spruce (Piceamariana (Mill.) B.S.P.) was initiated in Minnesota in 1974, with an objective of improving the inherent growth rate of the local population. This study reports some field results from the initial phase of the project. Study objectives were to (i) estimate genetic and environmental variance components of early (age 10 years) tree height, (ii) estimate expected genetic gains from various selection methods in three seedling seed orchards and a clonal seed orchard, and (iii) evaluate the effect that these selection methods have on inbreeding levels in the rogued seedling orchards. Additive genetic variance accounted for 15 to 22% of the phenotypic variance in three wind-pollinated family tests and 10% of the phenotypic variance across the tests. Expected gains from combined-index (family and individual) selection in the family test - seed orchards (selection of 22 to 27%) ranged from 4.6 to 6.1%. Family + within-family selection and individual selection were 18 and 32% less efficient, respectively. Index selection resulted in the highest estimated levels of inbreeding in the rogued orchards. However, the largest difference between the various selection methods resulted in a difference in the average inbreeding coefficient of less than 0.15%. Based on this small difference, index selection could be used in roguing similarly designed seedling seed orchards with minimal risk of elevated inbreeding levels.

Echinococcus granulosusstrain differentiation based on sequence heterogeneity in mitochondrial genes of cytochromecoxidase-1 and NADH dehydrogenase-1

Parasitology ◽  
2004 ◽  
Vol 128 (5) ◽  
pp. 569-575 ◽  
Author(s):  
A. OBWALLER ◽  
R. SCHNEIDER ◽  
J. WALOCHNIK ◽  
B. GOLLACKNER ◽  
A. DEUTZ ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Nadh Dehydrogenase ◽  
Genetic Variance ◽  
Significant Degree ◽  
Mitochondrial Genes ◽  
Moderate Degree ◽  
Sequence Heterogeneity ◽  
Pcr Product ◽  
Cattle Strain

Genetic analyses ofEchinococcus granulosusisolates from different intermediate host species have demonstrated substantial levels of variation for some genotype (strain) clusters. To determine the range of genetic variability within and between genotypes we amplified and cloned partialcox1andnadh1genes from 16 isolates ofE. granulosusfrom 4 continents. Furthermore, we sequenced different clones from a PCR product to analyse the intra-individual genetic variance. The findings showed a moderate degree of variance within single isolates and a significant degree of variance between the cluster of genotypes G1–G3 (sheep, Tasmanian sheep and buffalo strain), genotypes G4 (horse strain) and G5 (cattle strain) and the cluster of the genotypes G6 (camel strain) and G7 (pig strain). The variance of up to 2·2% within genotypes was relatively low compared with that of 4·3–15·7% among genotypes. The present results indicate that a re-examination of the classification of 5 genotypes ofEchinococcusis warranted. Hence, our data highly support a re-evaluation of the taxonomy of the clades G1–G3, G4, G5, G6/7 and G8 (cervid strain) within the genusEchinococcus.

scholarly journals INTERACTION BETWEEN NATURAL SELECTION FOR HETEROZYGOTES AND DIRECTIONAL SELECTION

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 163-168
Author(s):  
Margrith Wehrli Verghese
Keyword(s):  
Natural Selection ◽  
First Generation ◽  
Genetic Variance ◽  
Selection Response ◽  
Directional Selection ◽  
Simple Function ◽  
Small Populations ◽  
Gene Frequencies ◽  
Selection For

ABSTRACT When directional selection for an additively inherited trait is opposed by natural selection favoring heterozygous genotypes a selection plateau may be reached where genetic variance is present. The amount of response when this plateau is reached is a simple function of the selection response in the first generation and the intensity of natural selection. When selection is practiced in small populations, the sizes of the initial equilibrium gene frequencies are at least as important as the intensity of natural selection in determining the probability of fixing desirable alleles.

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