scholarly journals Assessing losses of genetic variability in the endangered Mallorquí horse

2010 ◽  
Vol 55 (No. 10) ◽  
pp. 456-462 ◽  
Author(s):  
I. Álvarez ◽  
L.J. Royo ◽  
L. Pérez-Pardal ◽  
I. Fernández ◽  
L. Payeras ◽  
...  

Information contained in the studbook of the endangered Mallorqu&iacute; horse was analysed to assess the genetic variability of the breed. Also, the effect of selection for coat colour variation was assessed using a set of 15 microsatellites genotyped on 68 Mallorqu&iacute; reproductive individuals previously diagnosed for the presence of the chestnut allele on the melanocortin-1 receptor gene. Mean inbreeding for the whole pedigree (310 individuals) was 2.5% while that for the individuals born during the last three years of recording (reference population) was 4.7%. Only 70% of all the founders have genetic representation in the reference population. A comparison of the parameters such as effective number of founders, effective number of ancestors and founder genome equivalents documented that the losses of founder genes occurred very soon after the implementation of conservation strategies. The parameter F<sub>IS</sub> computed from genealogical information was positive (0.029) for the whole population and negative (&ndash;0.024) for the reference population, thus illustrating the effort of the Mallorqu&iacute; horse breeders to avoid matings between relatives in later generations. A total of 14 individuals were heterozygotes for the chestnut allele (allele frequency of 10.6%). The rejection for reproduction of the chestnut heterozygote individuals would not affect the overall gene diversity of the population. However, the total allelic richness would decrease both at the within-subpopulation (1.2%) and total contribution level (0.4%). The chestnut heterozygote individuals are a within-breed reservoir of rare alleles that should be preserved to avoid risks for the future viability of the breed.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Salvatore Bordonaro ◽  
Anna Maria Guastella ◽  
Andrea Criscione ◽  
Antonio Zuccaro ◽  
Donata Marletta

The genetic variability of Pantesco and other two Sicilian autochthonous donkey breeds (Ragusano and Grigio Siciliano) was assessed using a set of 14 microsatellites. The main goals were to describe the current differentiation among the breeds and to provide genetic information useful to safeguard the Pantesco breed as well as to manage Ragusano and Grigio Siciliano. In the whole sample, that included 108 donkeys representative of the three populations, a total of 85 alleles were detected. The mean number of alleles was lower in Pantesco (3.7), than in Grigio Siciliano and Ragusano (4.4 and 5.9, resp.). The three breeds showed a quite low level of gene diversity (He) ranging from 0.471 in Pantesco to 0.589 in Grigio. The overall genetic differentiation index (Fst) was quite high; more than 10% of the diversity was found among breeds. Reynolds’ () genetic distances, correspondence, and population structure analysis reproduced the same picture, revealing that, (a) Pantesco breed is the most differentiated in the context of the Sicilian indigenous breeds, (b) within Ragusano breed, two well-defined subgroups were observed. This information is worth of further investigation in order to provide suitable data for conservation strategies.


2005 ◽  
Vol 143 (2-3) ◽  
pp. 209-216 ◽  
Author(s):  
L. M. MELUCCI ◽  
C. DÍAZ ◽  
C. A. MEZZADRA

The active germplasm Bank of the Integrated Unit (Facultad de Ciencias Agrarias, Unversidad Nacional de Mar del Plata and the Experimental Station of INTA) at Balcarce, keeps both in vivo (live herd) and in vitro Criollo Cattle (samples of semen and embryos cryogenically), with the aim of preserving genetic variability for potential future use. Parameters based on probable origin of genes, on population size and on the estimation of components of (co)variances for birth and weaning weights were estimated to evaluate the genetic variability of the material contained in the Bank. The information available came from 667 individuals, of which 84 had unknown parents, and 142 half-founders (only one parent known), having a mean number of births per year of 24 calves from four different sires. AI was performed during the mating season almost every year. The evolution of effective number of founders (fe), effective number of ancestors (fa), effective number of founder genomes (Ng) and the ratio fe/fa over different periods from the creation of the Bank, were analysed. Annual increase of inbreeding coefficient (F) was 0·2% and the effective population size (Ne) was estimated as 23, 14 and 25 individuals for the periods defined by years 1978–82, 1983–87 and 1993–97, respectively. The ratio fe/fa was higher in the years where the ratio number of sires/number of dams was lower, indicating that the impact of the effective number of sires is more important than the effective number of females in generating genetic bottlenecks. When the reference population was taken for the period 1989–97, 16·45 out of the 85·63 founders of the population made contributions not explained by other ancestors, but if possible losses of genomes due to genetic drift are considered, the number of genomes still present was reduced to 9·09 indicating a possible narrow genetic bottleneck in the last period. The Ng/fe ratio was 0·11, 0·10 and 0·11 for the reference populations defined by years 1989–92, 1993–97 and 1989–97, respectively. The main objective in germplasm conservation programmes should be the maintenance of genetic variability. Thus, matings in the population under conservation should be designed in order to mate those animals that maximize the effective number of genome founders (Ng) to avoid losses due to genetic drift.


Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1878
Author(s):  
Karolina Kasprzak-Filipek ◽  
Wioletta Sawicka-Zugaj ◽  
Zygmunt Litwińczuk ◽  
Witold Chabuz ◽  
Rūta Šveistienė ◽  
...  

There are many genes responsible for the appearance of different coat colours, among which the melanocortin 1 receptor gene (MC1R) plays an important role. The aim of the study was to characterize genetic variation in Central European cattle breeds based on polymorphism of the MC1R gene and factors determining their coat colour. The study was conducted on 290 individuals of the following breeds: Polish White-Backed (PW), Lithuanian White-Backed (LW), Polish Red (PR), Lithuanian Red (LR), Carpathian Brown (CB), Ukrainian Grey (UG), and Slovak Pinzgau (SP). Polymorphism at the MC1R gene locus was analysed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using two restriction enzymes: Cfr10I and SsiI. The proportions of alleles and genotypes in the MC1R locus indicates a strong relationship between polymorphism and the coat colour of cattle: The ED allele proved to be characteristic for the breeds with a white-backed coat (PW and LW), while the dominant allele in the red breeds (PR and LR) was E+. It is noteworthy that coat colour in the SP population was determined only by the recessive e allele, which resulted in the formation of a separate clade in the phylogenetic tree.


Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 25
Author(s):  
Caterina M. Antognazza ◽  
Isabella Vanetti ◽  
Vanessa De Santis ◽  
Adriano Bellani ◽  
Monica Di Francesco ◽  
...  

The reintroduction of the extinct beluga sturgeon (Huso huso L.), an anadromous species with economic and traditional relevance, is a priority in next conservation strategies in Northern Italy. The EU-LIFE NATURA project aims to reintroduce the beluga sturgeon in the Po River basin through a captive breeding program. Critical requirements for the success of the program are river connectivity and knowledge of genetic diversity of the selected broodstocks to ensure self-sustainability of reintroduced populations. Here, the four broodstocks used for the reintroduction of beluga sturgeon have been genetically screened, genotyping 13 loci and sequencing mitochondrial DNA cytochrome b (Cyt b) gene and the entire mitochondrial DNA control region (D-Loop). The four broodstocks showed a medium-high level of nuclear genetic variability and the presence of two sub-populations, evidencing a total level of inbreeding coefficients able to sustain the good potential as future breeders. Mitochondrial analyses showed a genetic variability comparable to wild populations, further strengthening the positive potential of the investigated broodstock. Therefore, this study, showed how the degree of genetic diversity found within the four broodstocks used for H. huso reintroduction in the Po River basin could be suitable to ensure the success of the program, avoiding the inbreeding depression associated with founder effect and captive breeding.


2020 ◽  
Vol 19 (1) ◽  
pp. 1508-1512
Author(s):  
Stefano Pallotti ◽  
Bathrachalam Chandramohan ◽  
Dario Pediconi ◽  
Cristina Nocelli ◽  
Antonietta La Terza ◽  
...  

2008 ◽  
Vol 71 (5) ◽  
pp. 434-439 ◽  
Author(s):  
I. Belle ◽  
L. Hou ◽  
M. Chen ◽  
N. K. Steiner ◽  
J. Ng ◽  
...  

Author(s):  
S. Mwangi ◽  
T.K. Muasya ◽  
E.D. Ilatsia ◽  
A.K. Kahi

Summary Pedigree analysis using genealogical information of 18 315 animals born between 1949 and 2008 was done to quantify genetic variability of the Sahiwal population in Kenya. Generation intervals for sire pathways were longer than dam pathways and increased over year periods, from about 4–16 years. The later was due to use of old bulls for breeding in the last 2 year groups and cessation of progeny testing in the year 2000. Average inbreeding level in last year period studied was 1.2 percent. Genetic variability of the population as assessed based on gene origin statistics decreased over the years. The ratio of effective number of founders to founders of 0.06 showed unequal contribution of founders to the reference population. However, since the founding population, ancestors contributed equally as shown by the ratio of f e/f a of 0.94, which could also be due to lack of effective selection in this population. The ratio of f g/f a of 0.63 indicated genetic loss of genetic variability occurred through genetic drift in the Kenyan Sahiwal population. The small number of ancestors (16) that accounted for 50 percent of the total variation in the reference population suggested overuse of a small number of some animals as parents over generations. The smaller ratio of f g/f e compared with f a/f e also confirms loss of genetic variability in the population by genetic drift than bottlenecks. Therefore the breeding strategy for the Sahiwal population in Kenya should incorporate tools that balance rate of genetic gain and the future rate of inbreeding.


2018 ◽  
Vol 55 (4) ◽  
pp. 233-238 ◽  
Author(s):  
Miho Kageyama ◽  
Atsushi Takenouchi ◽  
Keiji Kinoshita ◽  
Yoshiaki Nakamura ◽  
Masaoki Tsudzuki

2021 ◽  
Vol 35 (1) ◽  
Author(s):  
Abbas Jorkesh ◽  
Yousef Hamidoghli ◽  
Jamalali Olfati ◽  
Habibollah Samizadeh ◽  
Davood Bakhshi

The genetic variability of Froriepia subpinata Ledeb. Bail., an endangered Iranian endemic species, has been estimated with a total of 52 accessions using 20 markers including ISSR and IRAP. The results showed the polymorphic band produced by primers was 82.3%. The best mean values of genetic diversity parameters observed in ISSRs markers, being UBC873, UBC811, and UBC873 the best primers tested. The similarity range among accessions was 34.45% to 93.3%. The cluster analysis classified the accessions into five main groups that in totally, accessions with similarity in region generally were clustered in the same group. Overall, present study could provide elementary information for formulation of conservation strategies and invaluable elementary genetic information for next breeding or designing conservation programs.


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