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| 2. |
- Andonov, Sreten
(författare)
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Cutting corners: The impact of storage and DNA extraction on quality and quantity of DNA in honeybee (Apis mellifera) spermatheca
- 2023
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of our study was to investigate methods of short-term storage that allow preservation, transport and retrieval of genetic information contained in honeybee queen's spermatheca. Genotyping of the honeybee colony requires well ahead planned sample collection, depending on the type of data to be acquired. Sampling and genotyping of spermatheca's content instead of individual offspring is timesaving, allowing answers to the questions related to patriline composition immediately after mating. Such procedure is also cheaper and less error prone. For preservation either Allprotect Tissue Reagent (Qiagen) or absolute ethanol were used. Conditions during transportation were simulated by keeping samples 6-8 days at room temperature. Six different storing conditions of spermathecas were tested, complemented with two DNA extraction methods. We have analysed the concentration of DNA, RNA, and proteins in DNA extracts. We also analysed how strongly the DNA is subjected to fragmentation (through amplification of genetic markers ANT2 and tRNA(leu)-COX2) and whether the quality of the extracted DNA is suitable for microsatellite (MS) analysis. Then, we tested the usage of spermatheca as a source of patriline composition in an experiment with three instrumentally inseminated virgin queens and performed MS analysis of the extracted DNA from each spermatheca, as well as queens' and drones' tissue. Our results show that median DNA concentration from spermathecas excised prior the storage, regardless of the storing condition and DNA extraction method, were generally lower than median DNA concentration obtained from spermathecas dissected from the whole queens after the storage. Despite the differences in DNA yield from the samples subjected to different storing conditions there was no significant effect of storage method or the DNA extraction method on the amplification success, although fewer samples stored in EtOH amplified successfully in comparison to ATR storing reagent. However, we recommend EtOH as a storing reagent due to its availability, low price, simplicity in usage in the field and in the laboratory, and capability of good preservation of the samples for DNA analysis during transport at room temperature.
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- Andonov, Sreten
(författare)
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Direct Economic Impact Assessment of Winter Honeybee Colony Losses in Three European Countries
- 2021
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Ingår i: Agriculture. - : MDPI AG. - 2077-0472. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Honeybees are of great importance because of their role in pollination as well as for hive products. The population of managed colonies fluctuates over time, and recent monitoring reports show different levels of colony losses in many regions and countries. The cause of this kind of loss is a combination of various factors, such as the parasitic mite Varroa destructor, viruses, pesticides, management practices, climate change, and other stress factors. Having in mind that the economic aspect of honeybee colony losses has not been estimated, a pioneer effort was made for developing a methodology that estimates the economic impact of honeybee colony losses. Winter loss data was based on 2993 answers of the COLOSS standard questionnaire survey of honeybee winter colony losses for 2016/2017. In addition, market and financial data were used for each country. In a comparative analysis, an assessment on the economic impact of colony losses in Austria, Czechia, and Macedonia was made. The estimation considered the value of the colonies and the potential production losses of the lost colonies and of surviving but weak colonies. The direct economic impact of winter honeybee colony losses in 2016/2017 in Austria was estimated to be about 32 Mio; in Czechia, 21 Mio; and in Macedonia, 3 Mio. Economic impact reflects the different value levels in the three countries, national colony populations, and the magnitude of colony losses. This study also suggests that economic losses are much higher than the subsidies, which underlines the economic importance of honeybees for the agricultural sector.
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| 5. |
- Andonov, Sreten
(författare)
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Evaluating the potential for mating control in honey bee breeding in three SE European countries (preliminary results)
- 2022
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Konferensbidrag (refereegranskat)abstract
- The study was conducted to explore alternatives for mating control as a part of honey bee breeding programs for genetic improvement & conservation of local honey bee (Apis mellifera) populations in Croatia (HR), Macedonia (MK) and Slovenia (SI). We observed nuptial flights of 87 virgin queens (30 in HR, 35 in MK and 22 in SI) on potential sites. Mating success was related to the presence of drone producing colonies, but even at locations chosen for their isolation from known apiaries, mating success of 70% was achieved. On average, queens performed nuptial flights on 1.8 days in HR, 1.6 to 4.3 days in MK and 1.6 to 2.4 days in SI. Unsuccessful nuptial flights were two/threefold shorter than successful flights.
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| 6. |
- Andonov, Sreten
(författare)
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Evaluation of Suppressed Mite Reproduction (SMR) Reveals Potential for Varroa Resistance in European Honey Bees (Apis melliferaL.)
- 2020
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Ingår i: Insects. - : MDPI AG. - 2075-4450. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The miteVarroa destructorrepresents a great threat to honey bees and the beekeeping industry. The opportunity to select and breed honey bees that are naturally able to fight the mite stands a sustainable solution. This can be achieved by evaluation of the failure of mite reproduction (SMR, suppressed mite reproduction). We conducted a large European experiment to assess the SMR trait in different populations of honey bees spread over 13 different countries, and representing different honey bee populations. The first goal was to standardize and validate the SMR evaluation method, and then to compare the SMR trait between the different populations. Our results indicate that it is necessary to examine at least 35 brood cells infested by a single mite to reliably estimate the SMR score of any given colony. Several colonies from our dataset display high SMR scores, indicating that this trait is present within the European honey bee populations. No major differences could be identified between countries for a given population, or between populations in different countries. This study shows the potential to increase selection efforts to breedV. destructorhoney bee resistant populations. In the fight against theVarroa destructormite, selective breeding of honey bee (Apis melliferaL.) populations that are resistant to the parasitic mite stands as a sustainable solution. Selection initiatives indicate that using the suppressed mite reproduction (SMR) trait as a selection criterion is a suitable tool to breed such resistant bee populations. We conducted a large European experiment to evaluate the SMR trait in different populations of honey bees spread over 13 different countries, and representing different honey bee genotypes with their local mite parasites. The first goal was to standardize and validate the SMR evaluation method, and then to compare the SMR trait between the different populations. Simulation results indicate that it is necessary to examine at least 35 single-infested cells to reliably estimate the SMR score of any given colony. Several colonies from our dataset display high SMR scores indicating that this trait is present within the European honey bee populations. The trait is highly variable between colonies and some countries, but no major differences could be identified between countries for a given genotype, or between genotypes in different countries. This study shows the potential to increase selective breeding efforts ofV. destructorresistant populations.
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| 7. |
- Andonov, Sreten
(författare)
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Genetic-parameter estimation of milk yield in White Maritza sheep breed using different test day models
- 2023
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Ingår i: Archives Animal Breeding. - 0003-9438. ; 66, s. 253-263
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Tidskriftsartikel (refereegranskat)abstract
- The aims of this study were to estimate the genetic parameters of the test day milk yield (TDMY) of the White Maritza sheep breed population and to choose the most appropriate linear models for genetic-parameter estimation of test day milk yield. The White Maritza sheep breed is a multipurpose native sheep breed in Bulgaria. Test day milk yield data were collected from 1992 to 2015 (24 years). Milk yield recordings were made in 18 flocks according to the AC method (official milk recording by ICAR regulations). The database includes 8768 test day milk yield records belonging to 987 ewes. The pedigree file includes 1937 animals. Nine test day models (TDMs) were formulated and tested for the estimation of the genetic parameters of milk yield. The first three models were repeatability models (REP models), the second three were random regression models (RRMs), and the last three models were also random regression models with an added Ali and Schaeffer regression to describe the lactation curve using first-, second- and third-order polynomials. The average TDMY was 764.47 mL. There were no significant differences in the values of heritability (h2) calculated by the three REP models: REP1 0.355 ± 0.060, REP2 0.344 ± 0.047 and REP3 0.347 ± 0.060. The same applied to the repeatability coefficients, which, for the three REP models, were 0.384 ± 0.065, 0.376 ± 0.051 and 0.378 ± 0.065, respectively. Based on REP model 1, three models with random regression RRM1, RRM2 and RRM3 were constructed, which is associated with the use of first-, second- and third-order polynomials (for the random effects of both the animal and the permanent environment). The trajectories of h2 calculated by the three RRMs were not similar and demonstrated some differences, both at the beginning and in the middle of the milking period. The RRM with third-order polynomials demonstrated more genetic diversity until the 165th day of lactation, but Akaike information criterion (AIC), Bayesian information criterion (BIC) and log-likelihood (LogL) estimates were higher. The regression models with first- and second-degree polynomials were insufficient to reveal genetic diversity to a higher degree than REP model 1. The trend in the trajectories of h2 calculated by the three random regression models with Ali and Schaeffer regression models (ASRMs) was similar to that of random regression models without the Ali and Schaeffer regression incorporated. Although the noted advantages of the random regression models revealed, to a greater extent, the genetic diversity of test day milk yield, AIC, BIC and LogL estimates indicated that repeatability models achieved a better balance between complexity and fitness and a smaller prediction error compared to random regression models.
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| 8. |
- Andonov, Sreten
(författare)
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Modeling honey yield, defensive and swarming behaviors of Italian honey bees (Apis mellifera ligustica) using linear-threshold approaches
- 2019
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Ingår i: BMC genomic data. - : Springer Science and Business Media LLC. - 2730-6844 .- 1471-2156. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Background: Genetic improvement of honey bees is more difficult compared to other livestock, due to the very different reproductive behavior. Estimation of breeding values requires specific adjustment and the use of sires in the pedigree is only possible when mating of queens and drones is strictly controlled. In the breeding program of the National Registry for Italian Queen Breeders and Bee Producers the paternal contribution is mostly unknown. As stronger modeling may compensate for the lack of pedigree information, we tested two models that differed in the way the direct and maternal effects were considered. The two models were tested using 4003 records for honey yield, defensive and swarming behaviors of Italian honey bee queens produced between 2002 and 2014. The first model accounted for the direct genetic effect of worker bees and the genetic maternal effect of the queen, whereas model 2 considered the direct genetic effect of the queen without maternal effect. The analyses were performed by linear (honey production) and threshold (defensive and swarming behavior) single-trait models; estimated genetic correlations among traits were obtained by a three-trait linear-threshold model. Results: For all traits, the highest predictability (correlation between breeding values estimated with and without performance records) was obtained with model 2, where direct genetic effect of queens was considered. With this model, heritability estimates were 0.26 for honey yield, 0.36 for defensive behavior, and 0.34 for swarming behavior. Multi-trait estimation resulted in similar or higher heritability estimates for all traits. A low, positive genetic correlation (0.19) was found between honey yield and defensive behavior, whereas the genetic correlation between honey yield and swarming behavior was moderate (0.41). A strong, positive genetic correlation was found between defensive and swarming behaviors (0.62). Predictability for multi-trait evaluations was higher for honey yield (0.46) and defensive behavior (0.30) but almost identical for swarming behavior (0.45) compared to corresponding single-trait predictability. Conclusions: Multi-trait evaluation using a model that accounts for the direct genetic effect of queen was the best approach for breeding value estimation of Italian honey bees. The results suggest a new direction for selection of linear and categorical traits in breeding programs where drone origin is unknown.
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| 10. |
- Andonov, Sreten
(författare)
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Standard methods for direct observation of honey bee (Apis mellifera L.) nuptial flights
- 2024
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Ingår i: Journal of Apicultural Research. - 0021-8839 .- 2078-6913. ; 63, s. 65-75
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Tidskriftsartikel (refereegranskat)abstract
- Honey bees (Apis mellifera) have a peculiar and complex reproductive biology, with queens being polyandrous and mating with several drones during one or more mating (nuptial) flights in so-called drone congregation areas. Observing the virgin queens' and drones' flight behaviour provides data to understand and interpret a portion of the honey bees' complex reproductive process. Observing the behaviour of the virgin queens on the hive entrance also serves to estimate the distance from the mating place or potential drone congregation areas (DCAs) as well as to detect the presence of airborne drones in the area.In this paper, we provide a detailed description of the methodology used for observing queens' and drones' flights during the period of expected mating. In addition, we provide information about required equipment, tools as well as step by step description of the observation and recordkeeping process.
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