Does inbreeding affects developmental stability in Drosophila subobscura populations?

In the present paper, we focused on the coadaptive aspect of genetic variability at population level and its relation to genomic stress such as inbreeding. The paper evaluates the effects of an experimental reduction of average heterozygosity after fourteen generations of systematic inbreeding in laboratory conditions, on developmental stability in Drosophila subobscura populations from two ecologically and topologically distinct habitats, knowing that they possess a certain degree of genetic differences due to their different evolutionary histories. The aims were to analyze: (i) the variability change of wing size (length and width) among the inbred lines from both populations; (ii) the relations between homozigosity and level of fluctuating asymmetry as a potential measure of developmental instability, in inbred lines originating from two populations. Results for the wing size showed similar between line variability pattern across generations of systematic inbreeding in both populations. The obtained results suggest that variability of fluctuating asymmetry as a measure of developmental instability can not be related to homozygosity due to inbreeding per se, in both experimental populations.Rad je fokusiran na ko adaptivni aspekt genetičke varijabilnosti na nivou populacije i u odnosu na genomski stres kao što je inbriding. Analizirani su efekti eksperimentalnog smanjenja prosečne heterozigotnosti nakon 14 generacija sistematskog inbridinga u laboratorijskim uslovima na razvojnu stabilnost Drosophila subobscura populacija sa dva ekološki i topološki odvojena staništa, znajući da one poseduju odredjeni stepen genetičke diferencijacije usled različitih evolutivnih istorija. Ciljevi rada su bili da se analizira: (i) varijabilnost u promeni veličine krila (dužine i širine) medju inbidingovanim linijama i populacijama; (ii) odnosi izmedju homozigotizacije i nivoua fluktuirajuće asimetrije kao potencijalne mere razvojne nestabilnosti u inbridingovanim linijama obe populacije. Rezultati veličine krila pokazuju sličnu varijabilnost medju linijama obe populacije kroz generacije inbridinga. Dobijeni rezultati sugerišu da varijabilnost fluktuirajuće asimetrije kao mere razvojne nestabilnosti ne mogu biti povezani sa homozigotizacijom usled inbridinga per se, u obe eksperimentalne populacije.Projekat ministarstva br. 17301

Intra-species differentiation among Drosophila subobscura from different habitats in Serbia

Adaptation to different environmental conditions is a natural phenomenon that potentially leads to population subdivision. We surveyed genetic differentiation in inversion polymorphism within populations of Drosophila subobscura sampled in three ecologically different forest communities. The analysis of inversion polymorphism revealed significant differences between some pairs of samples in some gene arrangement frequencies of the A, U, and E chromosomes and some karyotype combination frequencies of the U chromosome, but significant differentiation within populations was not observed. It cannot be decided which evolutionary forces are responsible for the observed variability in inversion polymorphism.Adaptacija na različite sredinske uslove može uticati na diferencijaciju u okviru populacija. U ovom radu analizirana je genetička diferencijacija po inverzionom polimorfizmu u okviru populacija D. subobscura sakupljenih u tri ekološki različita staništa. Utvrđene su značajne razlike u učestalosti pojedinih hromozomskih aranžmana A, U i E hromozoma, i učestalosti pojedinih kombinacija kariotipova U hromozoma, ali nije utvrđena diferencijacija u okviru populacija. Razmatrani su evolutivni faktori koji bi mogli da budu odgovorni za uočenu varijabilnost u inverzionom polimorfizmu.Projekat ministarstva br. 14301

Sexual selection can reduce mutational load in Drosophila subobscura

According to theoretical predictions sexual selection can reduce mutational load through male mating success. Males of good genetic quality should be more successful in matings, compared to the males of low genetic quality, thus in this way females can prevent deleterious alleles to be transmitted to the next generation. We tested this hypothesis through set up of two experimental groups from same genetic pool, where in one group genetic quality was manipulated by ionizing radiation. Within each group opportunity for choosing mates was imposed: males and females had no choice or had multiple choice. Mutational load was measured through the variability of different fitness components: fecundity and egg-to-adult viability. Our results indicate that sexual selection can reduce mutational load, only for fecundity. Group with the presence of female choice exhibited higher fecundity than group in which sexual selection was experimentally eliminated, but only in 'irradiated' group. There was no overall difference in egg-to-adult viability between different sexual selection regimes in any of the group. It should be considered that sexual selection can cause sexual conflict, and potential opposite effects of sexual selection and sexual conflict on fitness. Genetic structure of populations, in terms of the level of mutational load, is an important factor which can determinate the role of sexual selection.Prema teorijskim očekivanjima seksualna selekcija može smanjivati mutaciona opterećenja u populacijama, preko uspešnosti mužjaka u parenju. Mužjaci koji su boljeg genetičkog kvaliteta bi trebalo da budu uspešniji u parenju od mužjaka lošijeg genetičkog kvaliteta. Na taj način bi ženke mogle da smanje prenošenje štetnih alela u sledeću generaciju. Ova hipoteza je testirana uspostavljanjem dve eksperimentalne grupe od istog genetičkog pula jedinki, pri čemu su u jednoj mutacije indukovane jonizujućim zračenjem. Unutar svake grupe je nametnuta mogućnost izbora u parenju: mužjaci i ženke nisu imali izbor, ili su imali višestruki izbor. Mutaciona opterećenja su merena preko dve komponente adaptivne vrednosti: fekunditeta i preživljavanja od stadijuma jaja do adulta. Dobijeni rezultati ukazuju da seksualna selekcija može imati uticaj na smanjivanje mutacionih opterećenja ali samo za fekunditet. U prisustvu seksualne selekcije su vrednosti fekunditeta bile veće u odnosu na vrednosti koje su dobijene kad je seksualna selekcija eksperimentalno uklonjena, ali samo u okviru 'ozračene' grupe. Razlike u preživljavanju od jaja do adulta između različitih režima seksualne selekcije nisu dobijene ni u jednoj od grupa. Kako seksualna selekcija često uzrokuje i seksualni konflikt, treba uzeti u obzir njihovo potencijalno delovanje u suprotnim pravcima na adaptivnu vrednost. Genetička struktura populacija, koja podrazumeva i veličinu mutacionih opterećenja, može biti važan faktor od koga će i zavisiti delovanje seksualne selekcija na adaptivnu vrednost.Projekat ministarstva br. 17301

Does inbreeding affects developmental stability in Drosophila subobscura populations?

In the present paper, we focused on the coadaptive aspect of genetic variability at population level and its relation to genomic stress such as inbreeding. The paper evaluates the effects of an experimental reduction of average heterozygosity after fourteen generations of systematic inbreeding in laboratory conditions, on developmental stability in Drosophila subobscura populations from two ecologically and topologically distinct habitats, knowing that they possess a certain degree of genetic differences due to their different evolutionary histories. The aims were to analyze: (i) the variability change of wing size (length and width) among the inbred lines from both populations; (ii) the relations between homozigosity and level of fluctuating asymmetry as a potential measure of developmental instability, in inbred lines originating from two populations. Results for the wing size showed similar between line variability pattern across generations of systematic inbreeding in both populations. The obtained results suggest that variability of fluctuating asymmetry as a measure of developmental instability can not be related to homozygosity due to inbreeding per se, in both experimental populations.Rad je fokusiran na ko adaptivni aspekt genetičke varijabilnosti na nivou populacije i u odnosu na genomski stres kao što je inbriding. Analizirani su efekti eksperimentalnog smanjenja prosečne heterozigotnosti nakon 14 generacija sistematskog inbridinga u laboratorijskim uslovima na razvojnu stabilnost Drosophila subobscura populacija sa dva ekološki i topološki odvojena staništa, znajući da one poseduju odredjeni stepen genetičke diferencijacije usled različitih evolutivnih istorija. Ciljevi rada su bili da se analizira: (i) varijabilnost u promeni veličine krila (dužine i širine) medju inbidingovanim linijama i populacijama; (ii) odnosi izmedju homozigotizacije i nivoua fluktuirajuće asimetrije kao potencijalne mere razvojne nestabilnosti u inbridingovanim linijama obe populacije. Rezultati veličine krila pokazuju sličnu varijabilnost medju linijama obe populacije kroz generacije inbridinga. Dobijeni rezultati sugerišu da varijabilnost fluktuirajuće asimetrije kao mere razvojne nestabilnosti ne mogu biti povezani sa homozigotizacijom usled inbridinga per se, u obe eksperimentalne populacije.Projekat ministarstva br. 17301

The effect of lead on the developmental stability of Drosophila subobscura through selection in laboratory conditions

Fluctuating asymmetry (FA), the increased variation of bilateral symmetry in a sample of individuals, can indicate disturbance in developmental stability caused by environmental and/or genomic stress. This developmental instability was analyzed in Drosophila subobscura maintained for seven generations on two different concentrations of lead in laboratory conditions. The FA4 index showed that the genotypes reared on the higher lead concentration were in developmental homeostasis, except for males in the F7 generation, for both wing size parameters. The results show that different degrees of lead pollution cause different responses to selection of the exposed population in laboratory conditions.Fluktuirajuća asimetrija predstavlja povećani stepen variranja bilateralno simetričnih karaktera u uzorku individua, i može da bude indikator remećenja nivoa razvojne stabilnosti pod uticajem genomskog i/ili sredinskog stresa. Stepen razvojne nestabilnosti je analiziran kod populacije Drosophila subobscura, uzgajane u laboratorijskim uslovima tokom sedam generacija na dve različite koncentracije olova. Rezultati FA4 indeksa su pokazali da genotipovi koji su uzgajani na višoj koncentraciji olova su u razvojnoj homeostazi, osim mužjaka u F7 generaciji, za oba posmatrana parametra krila. Rezultati ove studije ukazuju na to da različit stepen zagađenja olovom u laboratorijskim uslovima može izazivati različite odgovore na selekciju kod tretiranih populacija.Projekat ministarstva br. 14301

Intra-species differentiation among Drosophila subobscura from different habitats in Serbia

Adaptation to different environmental conditions is a natural phenomenon that potentially leads to population subdivision. We surveyed genetic differentiation in inversion polymorphism within populations of Drosophila subobscura sampled in three ecologically different forest communities. The analysis of inversion polymorphism revealed significant differences between some pairs of samples in some gene arrangement frequencies of the A, U, and E chromosomes and some karyotype combination frequencies of the U chromosome, but significant differentiation within populations was not observed. It cannot be decided which evolutionary forces are responsible for the observed variability in inversion polymorphism.Adaptacija na različite sredinske uslove može uticati na diferencijaciju u okviru populacija. U ovom radu analizirana je genetička diferencijacija po inverzionom polimorfizmu u okviru populacija D. subobscura sakupljenih u tri ekološki različita staništa. Utvrđene su značajne razlike u učestalosti pojedinih hromozomskih aranžmana A, U i E hromozoma, i učestalosti pojedinih kombinacija kariotipova U hromozoma, ali nije utvrđena diferencijacija u okviru populacija. Razmatrani su evolutivni faktori koji bi mogli da budu odgovorni za uočenu varijabilnost u inverzionom polimorfizmu.Projekat ministarstva br. 14301

Inversion polymorphism in populations of Drosophila subobscura from urban and non-urban environments

Populations of Drosophila subobscura from the urban area of Belgrade and from the locality, Deliblato, which is not under strong anthropogenic influence, were studied with the aim to characterize and compare their genetic structure by examining chromosomal inversion polymorphism. Additional analysis and comparison of this type of polymorphism with several other populations from different habitats in the central Balkans, was done. The obtained results indicate higher heterozygosity in the population from Belgrade. Despite being ecologically marginal and under strong and complex influences, this population did not show a decline in the number of inversions and it is not highly differentiated compared to the referent populations.Urađena je analiza inverzionog polimorfizma u populacijama Drosophila subobscura poreklom iz urbane sredine, lokalitet Botanička bašta u Beogradu, i sa lokaliteta u Deliblatu, Srbija, koji nije pod jakim antropogenim uticajem. Poređenjem inverzionog polimorfizma ove dve populacije međusobno, kao i sa drugim populacijama u regionu, ispitane su karakteristike i dinamika ovog tipa polimorfizma na centralnom Balkanu. Bez obzira što se populacija iz Beograda nalazi pod jakim antropogenim uticajem, ona ne pokazuje smanjenje broja inverzija i nije značajno diferencirana u poređenju sa geografski bliskim populacijama. Može se zaključiti da selektivni pritisak uzrokovan zagađenjem nije jak ili da je populacija prilagođena na zagađenje.Projekat ministarstva br. 14301

Sexual selection can reduce mutational load in Drosophila subobscura

According to theoretical predictions sexual selection can reduce mutational load through male mating success. Males of good genetic quality should be more successful in matings, compared to the males of low genetic quality, thus in this way females can prevent deleterious alleles to be transmitted to the next generation. We tested this hypothesis through set up of two experimental groups from same genetic pool, where in one group genetic quality was manipulated by ionizing radiation. Within each group opportunity for choosing mates was imposed: males and females had no choice or had multiple choice. Mutational load was measured through the variability of different fitness components: fecundity and egg-to-adult viability. Our results indicate that sexual selection can reduce mutational load, only for fecundity. Group with the presence of female choice exhibited higher fecundity than group in which sexual selection was experimentally eliminated, but only in 'irradiated' group. There was no overall difference in egg-to-adult viability between different sexual selection regimes in any of the group. It should be considered that sexual selection can cause sexual conflict, and potential opposite effects of sexual selection and sexual conflict on fitness. Genetic structure of populations, in terms of the level of mutational load, is an important factor which can determinate the role of sexual selection.Prema teorijskim očekivanjima seksualna selekcija može smanjivati mutaciona opterećenja u populacijama, preko uspešnosti mužjaka u parenju. Mužjaci koji su boljeg genetičkog kvaliteta bi trebalo da budu uspešniji u parenju od mužjaka lošijeg genetičkog kvaliteta. Na taj način bi ženke mogle da smanje prenošenje štetnih alela u sledeću generaciju. Ova hipoteza je testirana uspostavljanjem dve eksperimentalne grupe od istog genetičkog pula jedinki, pri čemu su u jednoj mutacije indukovane jonizujućim zračenjem. Unutar svake grupe je nametnuta mogućnost izbora u parenju: mužjaci i ženke nisu imali izbor, ili su imali višestruki izbor. Mutaciona opterećenja su merena preko dve komponente adaptivne vrednosti: fekunditeta i preživljavanja od stadijuma jaja do adulta. Dobijeni rezultati ukazuju da seksualna selekcija može imati uticaj na smanjivanje mutacionih opterećenja ali samo za fekunditet. U prisustvu seksualne selekcije su vrednosti fekunditeta bile veće u odnosu na vrednosti koje su dobijene kad je seksualna selekcija eksperimentalno uklonjena, ali samo u okviru 'ozračene' grupe. Razlike u preživljavanju od jaja do adulta između različitih režima seksualne selekcije nisu dobijene ni u jednoj od grupa. Kako seksualna selekcija često uzrokuje i seksualni konflikt, treba uzeti u obzir njihovo potencijalno delovanje u suprotnim pravcima na adaptivnu vrednost. Genetička struktura populacija, koja podrazumeva i veličinu mutacionih opterećenja, može biti važan faktor od koga će i zavisiti delovanje seksualne selekcija na adaptivnu vrednost.Projekat ministarstva br. 17301

Synergistic effect of environmental and genomic stress on wing size of drosophila subobscura

Growing anthropogenic influence on every aspect of environment arise important issues regarding the ability of populations and species to adapt to variant pressures. Lead is one of the most present contaminants in the environment with detrimental influence on organisms and populations. In combination with genomic stress, lead may act synergistically, leading to reduction in adaptive values. We sampled two Drosophila subobscura populations, from ecologically different habitats and established differences in genetic backgrounds and population histories. In order to establish different levels of genome heterozygosity, series of intra-line, intra-population and between population crosses were made. The progeny was reared on a standard Drosophila medium and a medium with 200μg/mL of lead acetate and right wing of approximately 4000 individuals was used for geometric morphometric analysis of wing size. Results showed that lead significantly reduces wing size and that magnitude of this reduction is dependent on genetic background, indicating synergistic effect of genomic and environmental stress. There is also an indication of strong female origin influence on the outcome of hybridization when source of environmental stress is lead. Our results showed that the genetic structure of populations is of great importance for population fitness in anthropogenic induced stressful conditions. Further studies of synergistic effect of genetic and environmental stress are needed, as well as studies of its outcome in natural populations.Genetika (2016), 48(3): 1039-105

Mating behavior as an indicator of quality of Drosophila subobscura males?

According to current theoretical predictions, any deleterious mutations that reduce nonsexual fitness may have a negative influence on mating success. This means that sexual selection may remove deleterious mutations from the populations. Males of good genetic quality should be more successful in mating, compared to the males of lower genetic quality. As mating success is a condition dependent trait, large fractions of the genome may be a target of sexual selection and many behavioral traits are likely to be condition dependent. We manipulated the genetic quality of Drosophila subobscura males by inducing mutations with ionizing radiation and observed the effects of the obtained heterozygous mutations on male mating behavior: courtship occurrence, courtship latency, mating occurrence, latency to mating and duration of mating. We found possible effects of mutations. Females mated more frequently with male progeny of nonirradiated males and that these males courted females faster compared to the male progeny of irradiated males. Our findings indicate a possible important role of sexual selection in purging deleterious mutations