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This study presents evidence, using sequences of ribosomal 16S and COI mtDNA, for the presence of two mitochondrial genomes in Perumytilus purpuratus. This may be considered evidence of doubly uniparental mtDNA inheritance. The presence of the two types of mitochondrial genomes differentiates females from males. The F genome was found in the somatic and gonadal tissues of females and in the somatic tissues of males; the M genome was found in the gonads and mantle of males only. For the mitochondrial 16S region, ten haplotypes were found for the F genome (nucleotide diversity 0.004), and 7 haplotypes for the M genome (nucleotide diversity 0.001), with a distance Dxy of 0.125 and divergence Kxy of 60.33%. For the COI gene 17 haplotypes were found for the F genome (nucleotide diversity 0.009), and 10 haplotypes for the M genome (nucleotide diversity 0.010), with a genetic distance Dxy of 0.184 and divergence Kxy of 99.97%. Our results report the presence of two well-differentiated, sex-specific types of mitochondrial genome (one present in the male gonad, the other in the female gonad), implying the presence of DUI in P. purpuratus. These results indicate that care must be taken in phylogenetic comparisons using mtDNA sequences of P. purpuratus without considering the sex of the individuals.

Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male–female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male–female kinship effect was stronger in high‐latitude populations, suggesting that females from low‐latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.

This study examines the genetic connectivity between natural banks of Chilean mussel, Mytilus chilensis, located in Reloncav ı Fjord. This sector is the principal source of seed for commercial farming and has the second-largest aquaculture production volume in the country. The objects of this work are as follows: (1) to estimate the degree of connectivity between patches (microscale) located in the intertidal/subtidal zones, evaluating the presence of selection processes; and (2) to identify connectivity patterns by gene flow between subpopulations (mesoscale) in order to determine whether they all correspond to a common population (metapopulation). We analysed individuals distributed in the intertidal and subtidal zones of five locations by sequencing the mitochondrial cytochrome oxidase I gene and eight nuclear DNA microsatellite loci. Comparison of the two tidal zones presented differences revealed by the COI gene. The locations presented low genetic differentiation; however, differences were found in both markers at the mouth of the fjord.The differences between the tidal zones may result from differentiated natural selection processes between the intertidal and subtidal environments, with those in the intertidal subjected to greater selective pressure. There is effective connectivity between the locations, facilitated by the capacity for dispersion of the larvae and certain oceanographic processes, which would also explain the differences observed in the location at the mouth of the fjord. Because these banks sustain mussel aquaculture activity throughout the country, it is important to take measures to ensure their proper maintenance, observing all the indicators including their genetic diversity and structure.