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In contrast to the nuclear genome, the mitochondrial genome does not follow Mendelian laws of inheritance. The nuclear genome of meiotic progeny comes from the recombination of both parental genomes, whereas the meiotic progeny could inherit mitochondria from one, the other, or both parents. In fact, one fascinating phenomenon is that mitochondrial DNA in the majority of eukaryotes is inherited from only one particular parent. Typically, such unidirectional and uniparental inheritance of mitochondrial DNA can be explained by the size of the gametes involved in mating, with the larger gamete contributing towards mitochondrial DNA inheritance. However, in the human fungal pathogen Cryptococcus neoformans, bisexual mating involves the fusion of two isogamous cells of mating type (MAT) a and MATα, yet the mitochondrial DNA is inherited predominantly from the MATa parent. Although the exact mechanism underlying such uniparental mitochondrial inheritance in this fungus is still unclear, various hypotheses have been proposed. Elucidating the mechanism of mitochondrial inheritance in this clinically important and genetically amenable eukaryotic microbe will yield insights into general mechanisms that are likely conserved in higher eukaryotes. In this review, we highlight studies on Cryptococcus mitochondrial inheritance and point out some important questions that need to be addressed in the future. [ABSTRACT FROM AUTHOR]

In eukaryotic cells, mitochondria play essential roles by generating the universal energy currency, adenosine triphosphate (ATP), through oxidative phosphorylation to support cellular activities. Similar to chloroplasts in plants and algae, but unlike other intracellular organelles, mitochondria contain their own genetic materials. The mitochondrial genes and genomes are inherited differently and independently from that of nuclear genes and genomes. While uniparental (and maternal) mitochondrial inheritance is the dominant pattern, there is a surprisingly large diversity of other inheritance modes, especially in fungi. Closely related species, or even different strains of the same species, can have different mitochondrial inheritance patterns in the fungal world. In this review, we describe the diversity of mitochondrial DNA inheritance patterns with an emphasis on fungi. Whenever possible, the mitochondrial inheritance patterns observed in fungi are compared with those in other eukaryotes to draw general conclusions about the mechanisms of mitochondrial inheritance in eukaryotes. The inheritance patterns derived from both laboratory crosses and natural populations are reviewed. In addition, we discuss the potential roles of hybridization on mitochondrial inheritance. [ABSTRACT FROM AUTHOR]

Roughly 18,000 species are described annually as new to science, while estimated extinction rates are comparable to or even exceeding these new discoveries. Considering the estimates of up to 15 million extant eukaryotic species on Earth, of which only about 2 million have been described so far, there has been a recent 'boom' of new potential approaches to more quickly discover and describe the millions of unknown species. This deficit is particularly noted in hyperdiverse taxa, as the current rate of species discovery is considered too slow. Recently, a 'minimalist' alpha taxonomic approach was proposed, relying solely on DNA barcoding and a habitus photograph, in a claimed effort to expedite the naming of new species to combat the so-called taxonomic impediment. In this paper, we point to limitations of minimalist taxonomy, present arguments in favour of the integrative approach, and finally explore a number of potential solutions to combat the taxonomic impediment in hyperdiverse taxa without sacrificing utility and quality for apparent speed and quantity. [ABSTRACT FROM AUTHOR]

In the mating of filamentous basidiomycetes, dikaryotic mycelia are generated through the reciprocal movement of nuclei to a monokaryotic cytoplasm where a nucleus of compatible mating type resides, resulting in the establishment of two different dikaryotic strains having the same nuclei but different mitochondria. To better understand the role of mitochondria in mushrooms, we created four sets of dikaryotic strains of Lentinula edodes, including B2 × E13 (B2 side) and B2 × E13 (E13 side), B5 × E13 (B5 side) and B5 × E13 (E13 side), E8 × H3 (E8 side) and E8 × H3 (H3 side), and K3 × H3 (K3 side) and K3 × H3 (H3 side). The karyotypes and mitochondrial types of the dikaryotic strains were successfully identified by the A mating type markers and the mitochondrial variable length tandem repeat markers, respectively. Comparative analyses of the dikaryotic strains on the mycelial growth, substrate browning, fruiting characteristics, and mitochondrial gene expression revealed that certain mitochondria are more effective in the mycelial growth and the production of fruiting body, possibly through the activated energy metabolism. Our findings indicate that mitochondria affect the physiology of dikaryotic strains having the same nuclear information and therefore a selection strategy aimed at mitochondrial function is needed in the development of new mushroom strain. [ABSTRACT FROM AUTHOR]

The Persian Gulf, an enclosed sea connected to the Gulf of Oman through the narrow Strait of Hormuz, is known as the world's hottest sea. Owing to its harsh environmental conditions, genetic isolation has been proposed for the Gulf's biota. During the present study, population genetic and phylogeographic analyses were carried out focusing on potential barriers to dispersal in some polychaete populations between the Persian Gulf and the Gulf of Oman. Ninety-three specimens from three defined spatial populations of three Hydroides species, H. bulbosa, H. elegans and H. operculata, were sequenced for regions of two nuclear ribosomal (18S and ITS2) and two mitochondrial (COI and Cyt-b) genes to compare the genetic structure among the sampled populations. Haplotype networks of the three species showed no significant genetic differentiation and were consistent with their geographic distribution patterns. Population genetic analyses such as pairwise FST, nucleotide diversity and neutrality tests revealed some levels of intraspecific genetic diversities, suggesting different demographic histories. The genetic diversity observed in the more conservative genes (18S, Cyt-b, COI) in populations of H. elegans and H. operculata could reflect a more diverse genetic structure along their entire distribution range unlike the endemic species, H. bulbosa that presented a unique haplotype for each of those genes. Using Extended Bayesian Skyline plot analyses, populations of H. bulbosa and H. operculata showed signs of recent demographic expansion within the post-glacial transgression time frame of the Persian Gulf, while populations of H. elegans remained relatively constant. Another finding of the present study is the possible indication of heteroplasmy in H. elegans where two distinct mitochondrial lineages with about 11% of genetic divergence seem to coexist in the same individuals. We discuss also the alternative explanation of NUMTs (nuclear mitochondrial DNA), but regard it as substantially less likely. [ABSTRACT FROM AUTHOR]

The structure and composition of the mitogenome of a bivalve mollusk, denoted as Mactra sp. (MT780813), has been obtained. The genome has a variable organization: it includes 12 protein-coding genes, 28 tRNAs, and two rRNA genes. Its content is sufficiently different from that of nearest specimen, accessed from GenBank, supposedly belonging to the other gender. All genes are encoded on the "+"-strand. All protein-coding genes are initiated with ATG codon. Analysis confirms the close topological position of the GenBank Mactra chinensis (KJ754823) and our M. sp. specimen on gene tree. Above data suggesting female- vs. male-type mitogenomes or cryptic species presence. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome of hard-shelled mussel was sequenced and annotated, it is 16,625 bp in length and contains 12 protein-coding genes (ATP8 is absent, as in most species in Mytilus), two ribosomal RNA genes and 22 transfer RNA genes. The content of A + T (63.2%) base pairs was higher than that of the G + C (36.8%) base pairs in the mitochondrial genome sequences, which indicated that the base composition is biased. Phylogenetic analysis based on neighbour-join of the twelve protein-coding genes showed that M. coruscus has closer relationships with M. californianus, which indicated that M. coruscus belongs to the Mytilidae family. This work provides general information on the evolution of cultured Mytilidae. [ABSTRACT FROM AUTHOR]

Haslea ostrearia (Gaillon) Simonsen is famous among diatoms for producing a blue pigment. Genome sequencing of different strains of H. ostrearia led to the discovery of the complete genomes of two new bacilladnaviruses, HOV-148 and HOV-235. The DNA sequences of these viruses were identified in H. ostrearia strains that had been maintained for several years in a culture collection. Some of these strains are the products of in vitro episodes of auxosporulation and thus have never been in contact with their natural biotope. At 4567 and 4538 bp, the HOV-148 and HOV-235 genomes are shorter than those of most diatom-infecting viruses known to date. They each contain four open reading frames and display highest similarities with sequences from viruses found in a gastropod from New Zealand, a proximity confirmed by phylogenetic analysis. HOV-148 and HOV-235 were identified in three clones of H. ostrearia that were collected in oyster ponds from distinct locations in the Bay of Bourgneuf (France). Given that our search for similar viral sequences in genomic data derived from other sub-populations or species of the genus Haslea throughout the world was unsuccessful, we hypothesize that these viruses could have a link with the peculiar biotope of the oyster ponds. [ABSTRACT FROM AUTHOR]

The genus Xenostrobus consists of small, marine and estuarine mussels that all appear similar externally. One of its estuarine species, Xenostrobus securis, with a native range in New Zealand and Australia, has become invasive in the Northern Hemisphere. No genetic data are available to determine if X. securis populations from the two countries are conspecific. Additionally, marine Xenostrobus from New Zealand have often been regarded as a species, X. neozelanicus, distinct fromthe marine Australian species X. pulex. We combined new DNA sequences with published data to assess the taxonomic status of New Zealand Xenostrobus. The data comprised 658 aligned bases of mitochondrial cytochrome c oxidase subunit I (COI) gene and 331 bases of nuclear histone H3. There was no evidence that X. securis populations from Australia and New Zealand are specifically distinct. Northern Hemisphere specimens of X. securis belonged to Australian, not New Zealand, clades in phylogenetic analyses of COI data, suggesting the former country as their more likely original source. The results confirm that X. neozelanicus and X. pulex are distinct species and for nomenclatural completeness for this taxonomic decision a lectotype is designated for Mytilus ater Zelebor in Dunker and Zelebor, 1866 [ = Modiolus neozelanicus Iredale, 1915]. [ABSTRACT FROM AUTHOR]

The controversy surrounding the origin of antitropical distribution of Mytilus mussels and the taxonomic status of southern hemisphere populations remain unsolved, despite the efforts. One of the limiting factors remains the lack of the complete sequences of the representative mitochondrial genomes which would allow their proper comparison with the relatively well-represented northern hemisphere congeneric mussels. To fill this gap we sequenced the representative maternal (F) genome of a native Chilean mussel. The genome is 16,748bp long and structurally identical to the northern hemisphere M. edulis and M. galloprovincialis F genomes. However, the genetic distance from them (≈5%) is twice as high as the maximum distance between them (<2.5%). Thus, the notion that the name M. chilensis should be used for native Chilean Mytilus mussels, with the same rank as M. galloprovincialis and M. edulis is supported. [ABSTRACT FROM AUTHOR]

Doubly uniparental inheritance (DUI) results in the existence of two gender-specific, divergent mtDNA lineages within a single species. Under DUI, the female genome (F) is transmitted from mothers to the whole offspring, and the male genome (M) is transmitted exclusively from fathers to sons. This system was first described in a marine musselsMytilus edulisinhabiting European coastal waters, over a decade ago. Despite that, the complete sequence of the M genome from the EuropeanM. edulismussels remained unknown. Here we announce it for the first time. The announcement is based on the two haplotypes isolated from heteroplasmic males of EuropeanM. edulissampled at two moderately distant locations: southern North Sea and western Baltic. The two M genomes are quite similar both in length (16,631 and 16,632 bp) and in sequence (98.3%). Furthermore, both newly sequenced genomes are closely related to the genomes described from BalticM. trossulus. [ABSTRACT FROM PUBLISHER]

We assembled mitogenomes from 21 ant workers assigned to four morphospecies (E. ruidum spp. 1-4) and putative hybrids of the Ectatomma ruidum complex (E. ruidum spp. 2x3), and to E. tuberculatum using NGS data. Mitogenomes from specimens of E. ruidum spp. 3, 4 and 2-3 had a high proportion of polymorphic sites. We investigated whether polymorphisms in mitogenomes are due to nuclear mt paralogues (numts) or due to the presence of more than one mitogenome within an individual (heteroplasmy). We did not find loss of function signals in polymorphic protein-coding genes, and observed strong evidence for purifying selection in two haplotype-phased genes, which indicate the presence of two functional mitochondrial genomes coexisting within individuals instead of numts. Heteroplasmy due to hybrid paternal leakage is not supported by phylogenetic analyses. Our results reveal the presence of a fast-evolving secondary mitochondrial lineage of uncertain origin in the E. ruidum complex. [ABSTRACT FROM AUTHOR]

Several bivalve species, including marine musselsMytilusare atypical in having two gender-specific and highly divergent mtDNA genomes. This peculiar genetic system allows not only the recombination to occur but also facilitates its detection. Previous reports associated the existence of mosaic recombinant haplotypes with the switch of their transmission route. Here we report nearly complete sequence of a mitochondrial genome isolated from a homoplasmic female individual of MediterraneanMytilus galloprovincialis. The genome has clear phylogenetic affinity with and organization identical to theM. galloprovincialisfemale haplotypes, in the coding part. However, the genome is very large, approximately 20,600 bp long, exclusively due to a long and complex control region. It contains an array of repeats, some of which are degenerated. A large part of the control region is derived from the paternal genome. This finding shows that not all haplotypes with recombinant control regions must be paternally inherited inMytilus. [ABSTRACT FROM AUTHOR]

The current understanding of the genetic diversity of the phytopathogenic fungusUstilago maydisis limited. To determine the genetic diversity and structure ofU. maydis, 48 fungal isolates were analyzed using mitochondrial simple sequence repeats (SSRs). Tumours (corn smut or ‘huitlacoche’) were collected from different Mexican states with diverse environmental conditions. Using bioinformatic tools, five microsatellites were identified within intergenic regions of theU. maydismitochondrial genome. SSRMUM4 was the most polymorphic marker. The most common repeats were hexanucleotides. A total of 12 allelic variants were identified, with a mean of 2.4 alleles per locus. An estimate of the genetic diversity using analysis of molecular variance (AMOVA) revealed that the highest variance component is within states (84%), with moderate genetic differentiation between states (16%) (FST = 0.158). A dendrogram generated using the unweighted paired-grouping method with arithmetic averages (UPGMA) and the Bayesian analysis of population structure grouped theU. maydisisolates into two subgroups (K = 2) based on their shared SSRs. [ABSTRACT FROM PUBLISHER]

Mitochondria are best known for their role in the production of ATP; however, recent research implicates other mitochondrial functions in the virulence of human pathogenic fungi. Inhibitors of mitochondrial succinate dehydrogenase or the electron transport chain are successfully used to combat plant pathogenic fungi, but similar inhibition of mitochondrial functions has not been pursued for applications in medical mycology. Advances in understanding mitochondrial function relevant to human pathogenic fungi are in four major directions: 1) the role of mitochondrial morphology in virulence, 2) mitochondrial genetics, with a focus on mitochondrial DNA recombination and mitochondrial inheritance 3) the role of mitochondria in drug resistance, and 4) the interaction of mitochondria with other organelles. Collectively, despite the similarities in mitochondrial functions between fungi and animals, this organelle is currently an under-explored potential target to treat medical mycoses. Future research could define and then exploit those mitochondrial components best suited as drug targets. [ABSTRACT FROM AUTHOR]

1. To explore the genetic diversity of Chinese indigenous chicken breeds, a 585 bp fragment of the mitochondrial DNA (mtDNA) region was sequenced in 102 birds from the Xichuan black-bone chicken, Yunyang black-bone chicken and Lushi chicken. In addition, 30 mtDNA D-loop sequences of Silkie fowls were downloaded from NCBI. The mtDNA D-loop sequence polymorphism and maternal origin of 4 chicken breeds were analysed in this study. 2. The results showed that a total of 33 mutation sites and 28 haplotypes were detected in the 4 chicken breeds. The haplotype diversity and nucleotide diversity of these 4 native breeds were 0.916 ± 0.014 and 0.012 ± 0.002, respectively. Three clusters were formed in 4 Chinese native chickens and 12 reference breeds. Both the Xichuan black-bone chicken and Yunyang black-bone chicken were grouped into one cluster. Four haplogroups (A, B, C and E) emerged in the median-joining network in these breeds. 3. It was concluded that these 4 Chinese chicken breeds had high genetic diversity. The phylogenetic tree and median network profiles showed that Chinese native chickens and its neighbouring countries had at least two maternal origins, one from Yunnan, China and another from Southeast Asia or its surrounding area. [ABSTRACT FROM PUBLISHER]

The subclass Pteriomorphia is a morphologically diverse and economically important group of Mollusca. We retrieved 42 mitochondrial genomes (mtGenomes) of Pteriomorphia and concatenated protein-coding genes, rRNAs and tRNAs to assess phylogenetic relationships and divergence times among the families with maximum likelihood (ML) and Bayesian inference (BI) analyses. Both ML and BI analyses strongly support the same topology except for the position ofAtrina pectinata. Our study confirms the monophyly of the families Arcidae, Mytilidae, Pteriidae, Ostreidae and Pectinidae. Within Pteriomorphia, we recovered two clusters, one comprising Mytilidae, Arcidae and Pectinidae, the other consisting of Ostreidae, Pteriidae and Pinnidae, but we did not confirm a basal position for any family. The phylogenetic trees suggest that Ostreidae, Pteriidae and Pinnidae should be grouped as the order Ostreoida. Divergence times of major families are estimated as follows: Arcidae, 315.9 Ma; Pectinidae, 384.4 Ma; Ostreidae, 240.8 Ma; Mytilidae, 390.8 Ma. Comparative analysis indicates a low-level codon usage bias (with an average of 50.29) in mtGenomes of Pteriomorphia. In Mytilidae and Ostreidae, the codon usage bias was under mutation pressure rather than selection. Contrastingly, mutation is not the main factor in defining the codon usage in Pectinidae and Pteriidae. Among Ostreidae, Pectinidae and Mytilidae, Ka/Ks ratios range from 0.00 to 1.22 and most values (89.11%) are less than 0.20, indicating that most genes are under strong negative or purifying selection. The protein-coding gene orders show dramatically different patterns in Pteriomorphia. There is no gene block even consisting of two genes that is shared by five families. [ABSTRACT FROM AUTHOR]

We have sequenced the female and male mtDNA ofUnio delphinusand inferred the Unionidae phylogeny using 41 complete mtDNA sequences. Additionally, we compared the concatenated mtDNA trees with those using single or combination of two mtDNA genes to identify the best genes to use in the absence of complete mitogenomes. The gender-specific mtDNAs ofU. delphinuscontain all Unionida mtDNA specific features. The mtDNA phylogeny supports the reciprocal monophyly of the gender-specific clades but it was inconclusive regarding Unionidae subfamilies relationships. The gene trees topologies usingND5or16S-rRNAwithND1were the closest trees to the mtDNA trees. [ABSTRACT FROM PUBLISHER]

A partial sequence of the mitochondrial cytochrome oxidase subunit I (COI) gene is widely used as a molecular marker for species identification in animals, also termed a DNA barcode. However, the presence of more than one sequence type in a single individual, also known as heteroplasmy, is one of the shortcomings of barcode identification. In this study, we examined the extent and divergence of COI heteroplasmy, including nuclear-encoded mitochondrial pseudogenes (NUMTs), at the genomic-DNA level from 13 insect species including orthopteranAnapodisma miramae, and a long fragment of mitochondrial DNA and cDNA fromA. miramaeas templates. When multiple numbers of clones originated from genomic DNA were sequenced, heteroplasmy was prevalent in all species and NUMTs were observed in five species. Long fragment DNA (∼13.5 kb) also is a source of heteroplasmic amplification, but the divergent haplotypes and NUMTs obtained from genomic DNA were not detected inA. miramae. On the other hand, cDNA was relatively heteroplasmy-free. Consistently, one dominant haplotype was always obtained from the genomic DNA-origin clones in all species and also from the long fragment- and cDNA-origin clones in the two tested individuals ofA. miramae. Furthermore, the dominant haplotype was identical in sequence, regardless of the DNA source inA. miramae. Thus, one possible solution to avoid the barcoding problem in relationship to heteroplasmy could be the acquisition of multiple numbers of barcoding sequences to determine a dominant haplotype that can be assigned as barcoding sequence for a given species. [ABSTRACT FROM AUTHOR]

The adulteration/substitution of meat has always been a concern for various reasons such as public health, religious factors, wholesomeness, and unhealthy competition in meat market. Consumer should be protected from these malicious practices of meat adulterations by quick, precise, and specific identification of meat animal species. Several analytical methodologies have been employed for meat speciation based on anatomical, histological, microscopic, organoleptic, chemical, electrophoretic, chromatographic, or immunological principles. However, by virtue of their inherent limitations, most of these techniques have been replaced by the recent DNA-based molecular techniques. In the last decades, several methods based on polymerase chain reaction have been proposed as useful means for identifying the species origin in meat and meat products, due to their high specificity and sensitivity, as well as rapid processing time and low cost. This review intends to provide an updated and extensive overview on the DNA-based methods for species identification in meat and meat products. [ABSTRACT FROM PUBLISHER]

The complete mitogenome ofAnodonta cygneais 15,613 bp long. This compact, circular molecule contains the set of 37 genes, typical for invertebrate mitogenomes, in the same order and orientation as in maternally inherited genomes of other bivalves from the same subfamily. There are only two unassigned regions longer than 200 bp (266 bp and 274 bp) and no indication of any supranumerary open reading frames. [ABSTRACT FROM PUBLISHER]

Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) is an exceptional mode of mtDNA transmission, restricted so far to the class of bivalves. We searched for DUI outside bivalves using the apple snailPomacea diffusa. It was an appropriate candidate to search for DUI for three reasons; it belongs to gastropods, which is the closest sister group to bivalves, it is gonochoristic and it has a strong sex bias in the progeny of different female individuals. These phenomena (gonochorism and sex-biased progeny) are also found in species with DUI. We searched for heteroplasmy in males and for high sequence divergence among mtDNA sequences obtained from male and female gonads. All sequences examined were identical. These data suggest that the mtDNA inP. diffusais maternally transmitted and DUI remains an exclusive characteristic of bivalves. [ABSTRACT FROM AUTHOR]

Veneridae is a diverse, commercially important, and cosmopolitan family. Here we present the complete mitochondrial genome of the clam Meretrix petechialis (Bivalvia: Veneridae). The genome is 19,567 bp in length, and contains 36 genes including 12 protein-coding genes, two ribosomal RNAs, and 22 transfer RNAs (tRNAs). All genes are encoded on the same strand. In contrast to the typical animal mitochondrial genomes, it lacks the protein-coding gene atp8. The other distinct features of the mitochondrial genome are that it has only one copy of trnS and a duplication of the trnQ gene. Mitochondrial gene orders are most highly rearranged in the class Bivalvia. Comparing the gene arrangements between M. petechialis and Venerupis philippinarum, we observe that they share four completely identical gene blocks, two large gene blocks cox1-L1-nad1-nad2-nad4L-I and cox2-P-cytb-rrnL-nad4-H-E-S2-atp6-nad3-nad5, and two small gene blocks containing tRNA genes only. After excluding tRNAs from the comparison, the gene arrangements between M. petechialis and V. philippinarum are the same except for translocations of the genes rrnS and cox3. We also present comparisons of gene arrangements between other molluscan species. [ABSTRACT FROM AUTHOR]

The complete mitochondrial DNA (mtDNA) sequences of the allotetraploid and red crucian carp were determined in this paper. We compared the complete mtDNA sequences between the allotetraploid and its female parent red crucian carp, and between the allotetraploid and its male parent common carp. The results indicated that the complete mtDNA nucleotide identity (99.7%) between the allotetraploid and its female parent red crucian carp was higher than that (89.0%) between the allotetraploid and its male parent common carp. Moreover, the analysis on the start and stop codons, overlaps and spacers, and phylogeny of the mt genomes indicated the genetic relationship between the allotetraploid and its female parent red crucian carp was closer than that between the allotetraploid and its male parent common carp. Our results indicated that the allotetraploid mt genome was strictly maternally inherited. Through maternal inheritance, the mt genome in the F11 allotetraploid displayed extremely high similarity to that in the female parent red crucian carp after 11 generations (from F1 to F11 hybrids). Such results indicated that the F11 allotetraploid possessed the stable inheritance characteristic. Thus the tetraploid stocks possessed the good base to form a new tetraploid species in the future. Since the establishment of the new tetraploid stocks has the great significance in analyzing evolutionary theory of vertebrate and in improving aquaculture industry, analysis of the mt genome and the elucidation of the variation of the mt genome in the allotetraploid and its parents proved that it was a useful genetic marker to monitor the variations in the progeny of the crosses. [ABSTRACT FROM AUTHOR]

The article informs that the sequence of the complete human genome was presented to the world by science, politics and commerce in June 2000. Substantial parts of that genome are still being mapped. However, as early as 1981 a complete sequence of another human genome was produced in Cambridge--not a sequence of nuclear DNA, but that of the mitochondrial DNA. Yet their functioning as standards and their ability to comply with everyday practice, tends to obscure their normative content and to make that inaccessible for interrogation.

Documents areas of the human neocortex linked to the upsurge of myopia in the 20th century. Prevalence of myopia in gifted populations; Effects of rising intelligence quotient on perceptions of age-related changes in mental abilities; Mechanisms for the inheritance of environmentally-induced changes in the brain; Behavioral influences and evolutionary implications; Brain size.

We initiated a clinical and genetic linkage study on members of a large Venezuelan family with hereditary hearing loss. A medical history and a physical examination were performed on 30 family members. Audiometry was carried out in 25 subjects, and in 2 additional children auditory brainstem responses were obtained. Additional testing (site-of-lesion, electronystagmography and computed tomography) was also obtained in a few subjects. DNA was extracted from blood samples from 25 family members. The type of deafness in this family is neurosensorial, non-syndromic and postlingual. The average age of onset of deafness is 7 years and there is a rapid progression leading to profound deafness. Deafness is possibly of cochlear origin and there is no associated vestibular pathology. Analysis of the pedigree discloses a maternal pattern of inheritance with a significant female predominance, compatible with a mutation of the mitochondrial DNA. The molecular DNA analysis for the known mitochondrial mutations are discussed. [ABSTRACT FROM AUTHOR]

Lamprotula tortuosa is the endemic species of freshwater pearl mussel in China. The complete F-type mitochondrial genome of L. tortuosa was first determined. This circle genome (15,722 bp in size) comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, except for COI, CYTB, ND6, and ND4L, with TTG, ATT, ATT, and ATA start codon, respectively; the remaining protein-coding genes initiated with the orthodox ATG start codon. There were 25 noncoding regions found throughout the mitogenome of L. tortuosa, ranging in size from 1 to 241 bp, the largest of which is between ND5 and tRNAGln (241 bp), but is shorter than the control region sequences(about 280 bp) of freshwater mussels from Poland and South Korea. [ABSTRACT FROM AUTHOR]

Aculamprotula tientsinensisis a rare and endemic species of freshwater mussel in China. This study firstly determined the complete F-type mitochondrial genome ofA. tientsinensis.The circle genome (15 695 bp) comprises 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, 1 FORF gene. Except forcob, nad5andnad6, the remaining protein-coding genes initiate with the orthodox start codon (ATG, ATA, ATT). There are 26 non-coding regions in the mitogenome ofA. tientsinensis, ranging in size from 1 to 229 bp. The base composition of the genome is A (37.83%), G (12.69%), T (25.43%) and C (24.06%). Gene order is identical to other female species of Unionidae but for Gonideinae. The phylogenetic analyses of Unionidae indicate thatA. tientsinensisis closely related toA. tortuosaandA. coreana, which belong to Unioninae. The complete mitogenome can deepen comparative and evolutionary genomics of Unionidae and be more comprehensive to parse the genetic relationship between the species and the ownership beyond species. [ABSTRACT FROM AUTHOR]

The complete F-type mitochondrial genome ofCuneopsis pisciculuswas first determined in this research. This circular genome (15,907 bp in size) contained 13 protein-coding genes, 22 tRNA genes and 2rRNA genes. The protein-coding genes initiated with orthodox ATG or ATA start codon. Twenty-five non-coding regions were found throughout the mitochondrial genome ofC. pisciculus, ranging in size from 1 to 326 bp. The maximum was betweentRNAGlnand geneND5(326 bp). [ABSTRACT FROM AUTHOR]

Anodonta anatinais a freshwater mussel of the family Unionidae. These mussels have a unique mitochondria inheritance system named doubly uniparental inheritance (DUI). Under DUI males have two, potentially very divergent mitochondrial genomes: F-type inherited from mother and M-type inherited from father. F-type is present in soma whereas M-type is present in gonadal tissues and sperm. Here we report two M-type sequences of complete mitochondrial genomes fromAnodonta anatina. They are 16,906 bp long and their sequences are similar (0.1% divergence). The genome organization is identical to the other Unionidean M-type genomes published to date. There are 38 genes, including the recently described M-type specific M ORF. The presence of tRNA-like repeat in one of the noncoding regions, suggests that the control region is located in this area. Nucleotide composition is quite extreme, with AT content (66.2%) higher than in any other of the six published Unionidean M genomes. [ABSTRACT FROM PUBLISHER]

The freshwater mussel Solenaia oleivora is considered threatened due to anthropogenic habitat modification and pollution. The complete F-type mitochondrial genome (mitogenome) of S. oleivora was first determined (GenBank accession no. KF296320). The length of this mitogenome is 16,392 bp with an AT content of 59.9%. There are 37 typical animal mitochondrial genes and a putative control region. Within the control region, 5 tandem repeats of a 106 bp element were identified. The gene order rearrangement of cox2-rrnS in F-type mitogenome compared to that of other freshwater mussels, is not unique for S. oleivora, but is shared with all other available freshwater mussels in the subfamily Gonideinae. The complete mitogenome can provide a basic data for the further studies on molecular taxonomy, phylogenetic analyses and conservation genetics. [ABSTRACT FROM AUTHOR]