Complex population structure and haplotype patterns in the Western European honey bee from sequencing a large panel of haploid drones.

Honey bee subspecies originate from specific geographical areas in Africa, Europe and the Middle East, and beekeepers interested in specific phenotypes have imported genetic material to regions outside of the bees' original range for use either in pure lines or controlled crosses. Moreover, imported drones are present in the environment and mate naturally with queens from the local subspecies. The resulting admixture complicates population genetics analyses, and population stratification can be a major problem for association studies. To better understand Western European honey bee populations, we produced a whole genome sequence and single nucleotide polymorphism (SNP) genotype data set from 870 haploid drones and demonstrate its utility for the identification of nine genetic backgrounds and various degrees of admixture in a subset of 629 samples. Five backgrounds identified correspond to subspecies, two to isolated populations on islands and two to managed populations. We also highlight several large haplotype blocks, some of which coincide with the position of centromeres. The largest is 3.6 Mb long and represents 21% of chromosome 11, with two major haplotypes corresponding to the two dominant genetic backgrounds identified. This large naturally phased data set is available as a single vcf file that can now serve as a reference for subsequent populations genomics studies in the honey bee, such as (i) selecting individuals of verified homogeneous genetic backgrounds as references, (ii) imputing genotypes from a lower-density data set generated by an SNP-chip or by low-pass sequencing, or (iii) selecting SNPs compatible with the requirements of genotyping chips.

Allozyme polymorphism and phylogenetic relationships in Apis mellifera subspecies selectively reared in Poland and Bulgaria.

The genetic variability of honey bee populations of three subspecies selectively reared in Poland (A. m. carnica and A. m. caucasica) and Bulgaria (A. m. macedonica-type rodopica) was studied using isoenzyme analysis of six enzyme systems (MDH-1, ME, EST-3, ALP, PGM and HK) corresponding to 6 loci. All loci were found to be polymorphic in the studied populations. Three alleles were detected at each locus: MHD-1 (MDH65, MDH80 and MDH100), Me (ME90, ME100 and ME106), EST-3 (EST94, EST100 and EST118), ALP (ALP80 ALP90 and ALP100), PGM (PGM80, PGM100 and PGM114) and HK (HK87, HK100 and HK110). The observed and expected heterozygosities (Ho and He) ranged from 0.196 (A. m. macedonica SM) to 0.265 (A. m. carnica MV) and from 0.224 (A. m. macedonica SM) to 0.273 (A. m. carnica GR), respectively. Allele frequencies of all loci were used to estimate Nei's (1972) genetic distance, which was found to range from 0.003 (between A. m. macedonica TR and SM and between A. m. carnica GR and MV populations) to 0.057 (between A. m. macedonica SM and A. m. caucasica populations). The estimated mean F(ST) value from allozyme data was 0.0364. A UPGMA dendrogram was obtained by genetic distance matrix methods; A. m. macedonica (type rodopica), A. m. carnica and A. m. caucasica populations represented different clades.

Honey Bee Queen Replacement: An Analysis of Changes in the Preferences of Polish Beekeepers through Decades.

We conducted a survey on honey bee (Apis mellifera) queen management. Data were collected every year from 1980 to 2018. In total, 2964 questionnaires were collected from all over Poland. We examined the trends by decade timeslot, apiary size, and geographical location. Regardless of the decade and the size of the apiary, on average, above 90% of Polish beekeepers replace old queens with new ones in their colonies. In general, during the observed period, beekeepers replaced almost 52% of their queens, 21% of which were purchased. In the last decade, there was an upward trend in the percentage of beekeepers replacing queens throughout the country. The involvement of purchased queens in colony management is associated with the size of the apiary, and it significantly grows with the number of colonies in the apiary. The percentage of purchased queens went up in all the voivodeships over time. Research and education in this area are needed in order to track the trends and further improve Polish beekeepers' practices.

Evaluation of Suppressed Mite Reproduction (SMR) Reveals Potential for Varroa Resistance in European Honey Bees (Apis mellifera L.).

In the fight against the Varroa destructor mite, selective breeding of honey bee (Apis mellifera L.) 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 of V. destructor resistant populations.

[Assessment of the correlation between proliferation defined by S-phase cell cycle and apoptosis after preoperative chemotherapy in osteosarcomas of children and adolescents]. / Ocena realizacji pomiedzy proliferacja okreslana faza s cyklu komórkowego a apoptoza, po przeprowadzonej wtepnej chemoterapii w miesakach kosciopochodnych u dzieci i mlodiezy.

Estimation of the S-phase of the cell cycle is applied to indicate the rate of cancer cells proliferation. This information is clinically useful, especially with the context of apoptosis (programmed cell death) stimulated by anticancer agents. The presented studies concerned above problems in children and adolescents osteosarcomas after preoperative chemotherapy. Flow cytometric method was used to analysis of S-phase cell cycle, aneuploidy and apoptosis (DNA histograms). The studies have shown that higher apoptotic index (percentage of apoptotic cells in "pre-G1/G0" position of DNA histograms), correlated with lower S-phase cell cycle and lower aneuploid fraction. It suggests that used chemotherapy treatment (Cisplatin, Adriamycin) induce apoptosis during S-phase cell cycle. Preliminary data are potentially important to predict clinical outcome after starting chemotherapy. This suggestion should be confirmed by estimation of other markers (early and late) of apoptosis.