Evolutionary history of sexual selection affects microRNA profiles in Drosophila sperm

Abstract

The presence of small RNAs in sperm is a relatively recent discovery and little is currently known about their importance and functions. Environmental changes including social conditions and dietary manipulations are known to affect the composition and expression of some small RNAs in sperm and may elicit a physiological stress response resulting in an associated change in gamete miRNA profiles. Here, we tested how microRNA profiles in sperm are affected by variation in both sexual selection and dietary regimes in Drosophila melanogaster selection lines. The selection lines were exposed to standard versus low yeast diet treatments and three different population sex ratios (male‐biased, female‐biased, or equal sex) in a full‐factorial design. After 38 generations of selection, all males were maintained on their selected diet and in a common garden male‐only environment prior to sperm sampling. We performed transcriptome analyses on miRNAs in purified sperm samples. We found 11 differentially expressed miRNAs with the majority showing differences between male‐ and female‐biased lines. Dietary treatment only had a significant effect on miRNA expression levels in interaction with sex ratio. Our findings suggest that long‐term adaptation may affect miRNA profiles in sperm and that these may show varied interactions with short‐term environmental changes.

The potential role of the mobile and non-coding genomes in adaptive response

“…In Drosophila for example, miRNA profiles in sperm collected from males from long-term selection lines exposed to varying sex ratios (equal sex ratio, male bias, or female bias for 38 generations) varied by 11 differentially expressed miRNA [13]. Notably, miR-9b-5pan miRNA that is enriched in male primordial germ cells onlywas reduced in the sperm from males sampled from female-biased lines compared to males from male-biased lines [14]. Whether these differentially expressed miRNAs affect the following generations is currently unclear and warrants further study.…”

Evolution and impact of socially transferred materials

“…Ejaculate [110], [111], [112] Ejaculate [113] Milk [30] Saliva [111] Eggs [99] Regurgitate [90] Nucleotides Ejaculate [97] Ejaculate [97] Milk [26] Proteins Ejaculate [103], [114] e.g. immunoregulatory factors, cytokines FRF [115] Ejaculate [116],…”

An epigenetic change in a moth is generated by temperature and transmitted to many subsequent generations mediated by RNA

“…In D . melanogaster it has been shown that long-term adaptation may affect miRNA profiles in sperm and that these may show varied interactions with short-term environmental changes [ 16 ]. Organisms appear to protect certain RNAs by design.…”

“…Additonally, piRNA cluster causes the complex changes in stresscoping behaviors, metabolism and stress-induced glucose release in the offspring [6,14]. In D. melanogaster it has been shown that long-term adaptation may affect miRNA profiles in sperm and that these may show varied interactions with short-term environmental changes [16]. Organisms appear to protect certain RNAs by design.…”