Mutation, recombination, and transposition occurring during meiosis provide the variation on which natural selection can act and the rates at which they occur are important parameters in models of evolution. The de novo mutation rate determines levels of genetic diversity, responses to ongoing selection, and levels of genetic load. Recombination breaks up haplotypes and reduces the effects of linkage, helping to spread beneficial alleles and purge deleterious ones. Transposable elements (TE) selfishly replicate themselves through the genome, imposing fitness costs on the host and introducing complex mutations that can affect gene expression and give rise to new genes. However, even for key evolutionary models such as Drosophila melanogaster and D. simulans few estimates of these parameters are available, and we have little idea of how rates vary between individuals, sexes, populations, or species. Here, we provide direct estimates of mutation, recombination, and transposition rates and their variation in a West African and a European population of D. melanogaster and a European population of D. simulans. Across 89 flies, we observe 58 single nucleotide mutations, 286 crossovers, and 89 TE insertions. Compared to the European D. melanogaster, we find the West African population has a lower mutation rate (1.67 vs. 4.86 * 10-9 site-1 gen-1) and transposition rate (8.99 vs. 23.36 * 10-5 copy-1 gen-1), but a higher recombination rate (3.44 vs. 2.06 cM/Mb). The European D. simulans population has a similar mutation rate to European D. melanogaster but a significantly higher recombination rate and a lower but not significantly different transposition rate. Overall, we find paternal-derived mutations are more frequent than maternal ones in both species.

The rates of mutation, recombination, and transposition are core parameters in models of evolution. They impact genetic diversity, responses to ongoing selection, and levels of genetic load. However, even for key evolutionary model species such asDrosophila melanogasterandD. simulans, few estimates of these parameters are available, and we have little idea of how rates vary between individuals, sexes, or populations. Knowledge of this variation is fundamental for parameterizing models of genome evolution. Here, we provide direct estimates of mutation, recombination, and transposition rates and their variation in a West African and a European population ofD. melanogasterand a European population ofD. simulans. Across 89 flies, we observe 58 single nucleotide mutations, 286 crossovers, and 89 transposable elements (TE) insertions. Compared to the EuropeanD. melanogaster, we find the West African population has a lower mutation rate (1.67 vs. 4.86 × 10-9 site-1 gen-1) and a lower transposition rate (8.99 vs. 23.36 × 10-5 copy-1 gen-1), but a higher recombination rate (3.44 vs. 2.06 cM/Mb). The EuropeanD. simulanspopulation has a similar mutation rate to EuropeanD. melanogaster, but a significantly higher recombination rate and a lower, but not significantly different, transposition rate. Overall, we find paternal-derived mutations are more frequent than maternal ones in both species. Our study quantifies the variation in rates of mutation, recombination, and transposition among different populations and sexes, and our direct estimate of these parameters inD. melanogasterandD. simulanswill benefit future studies in population and evolutionary genetics.

No abstract

Nutrition plays a pivotal role in the development of an organism. Drosophila melanogaster is an important model for nutritional research. The nutritional composition of semolina-jaggery diet and its effect on some developmental aspect of Harwich strain D. melanogaster was studied. Semolina- jaggery diet, which are product of wheat endosperm and cane sugar respectively are rich in carbohydrate, protein, and dietary sugars. Semolina-jaggery diet was prepared in 5%, 10% and 15% with corn flour diet as the control group. 15% semolina-jaggery had the highest percentage carbohydrate (15.12±0.30) while highest protein content was recorded in control diet (3.46±0.08). Fecundity of D. melanogaster reared on semolina-jaggery diet varied across days with 5% SJ having the highest mean number of eggs. The 10% SJ recorded the highest mean number of offspring across five generations but was lower to the offspring output of control group in all the five generations. The nutritional composition in the varying percentages of semolina-jaggery diet had significant effect on the egg laying and offspring output of Harwich strain Drosophila melanogaster.

Environmental conditions and anthropogenic activities at various temporal and spatial scales tend to shape the patterns of biodiversity. The family Drosophilidae serves as good bio indicator model in understanding ecological indices and species diversity interactions. The potential of Drosophila to serve as an environmental indicator lies on the cosmopolitan nature of this group and the sensitivity of the flies to environmental variables. This study analyzed the biodiversity of human-commensal Drosophila inhabiting vegetable markets located within the salt water mangrove (SWM), fresh water mangrove (FWM), rain forest (RF) and Southern Guinea Savanna (SGS) vegetation regions of Nigeria. Collections were made from sixteen (l6) vegetable markets using fermented banana as bait. A total of 1,077 fruit flies, composed of four different species of Drosophila belonging to the subgenera Sophophora, Zaprionus and an unidentified species were collected. Drosophila melanogaster of the subgenus Sophophora was predominant (82.5%) in all the sampled vegetation zones while the unidentified fruit fly species was the least (0.7%). The Simpson Diversity Index was lowest (0.13) for Southern Guinea Savanna indicating a higher diversity of fruit flies in the zone. The ecological index of temperature was significantly negatively correlated (-0.965) with Drosophila species diversity while human population was significantly positively correlated (0.832) with biodiversity. The results suggest D. melanogaster as the predominant human-commensal species irrespective of environmental factors and significant impacts of temperature and human population on the biodiversity of human-commensal Drosophila in Nigeria.