著者

Patwira Boonjing Yukari Masuta Kosuke Nozawa Atsushi Kato Hidetaka Ito

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.19-00046, (Released:2020-08-03)

参考文献数

34

被引用文献数

10

---

The Ty1/copia-like retrotransposon ONSEN is conserved among Brassica species, as well as in beans, including adzuki bean (Vigna angularis (Willd.) Ohwi & Ohashi), which is one of the economically important crops in Japan. ONSEN has acquired a heat-responsive element that is recognized by plant heat stress defense factors, resulting in its transcription and the production of full-length extrachromosomal DNA under conditions with elevated temperatures. DNA methylation plays an important role in regulating the activation of this transposon in plants. Therefore, chemical inhibition of DNA methyltransferases has been utilized to study the effect of DNA methylation on transposon activation. To understand the effect of DNA methylation on ONSEN activation, Arabidopsis thaliana and adzuki bean seedlings were treated with zebularine, which is known to be an effective chemical demethylation agent. The results showed that ONSEN transcription levels were upregulated in zebularine-treated plants. Extrachromosomal DNA of ONSEN also accumulated in the treated plants.

著者

Naoki Osada

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.90, no.3, pp.133-145, 2015-06-01 (Released:2015-10-27)

参考文献数

120

被引用文献数

19 28

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Genetic diversity is a key parameter in population genetics and is important for understanding the process of evolution and for the development of appropriate conservation strategies. Recent advances in sequencing technology have enabled the measurement of genetic diversity of various organisms at the nucleotide level and on a genome-wide scale, yielding more precise estimates than were previously achievable. In this review, I have compiled and summarized the estimates of genetic diversity in humans and non-human primates based on recent genome-wide studies. Although studies on population genetics demonstrated fluctuations in population sizes over time, general patterns have emerged. As shown previously, genetic diversity in humans is one of the lowest among primates; however, certain other primate species exhibit genetic diversity that is comparable to or even lower than that in humans. There exists greater than 10-fold variation in genetic diversity among primate species, and I found weak correlation with species fecundity but not with body or propagule size. I further discuss the potential evolutionary consequences of population size decline on the evolution of primate species. The level of genetic diversity negatively correlates with the ratio of non-synonymous to synonymous polymorphisms in a population, suggesting that proportionally greater numbers of slightly deleterious mutations segregate in small rather than large populations. Although population size decline is likely to promote the fixation of slightly deleterious mutations, there are molecular mechanisms, such as compensatory mutations at various molecular levels, which may prevent fitness decline at the population level. The effects of slightly deleterious mutations from theoretical and empirical studies and their relevance to conservation biology are also discussed in this review.

著者

Natsuki Sugaya Shion Tanaka Kenji Keyamura Shunsuke Noda Genki Akanuma Takashi Hishida

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.23-00013, (Released:2023-06-16)

参考文献数

56

被引用文献数

1

---

Homologous recombination (HR) is a highly accurate mechanism for repairing DNA double-strand breaks (DSBs) that arise from various genotoxic insults and blocked replication forks. Defects in HR and unscheduled HR can interfere with other cellular processes such as DNA replication and chromosome segregation, leading to genome instability and cell death. Therefore, the HR process has to be tightly controlled. Protein N-terminal acetylation is one of the most common modifications in eukaryotic organisms. Studies in budding yeast implicate a role for NatB acetyltransferase in HR repair, but precisely how this modification regulates HR repair and genome integrity is unknown. In this study, we show that cells lacking NatB, a dimeric complex composed of Nat3 and Mdm2, are sensitive to the DNA alkylating agent methyl methanesulfonate (MMS), and that overexpression of Rad51 suppresses the MMS sensitivity of nat3Δ cells. Nat3-deficient cells have increased levels of Rad52-yellow fluorescent protein foci and fail to repair DSBs after release from MMS exposure. We also found that Nat3 is required for HR-dependent gene conversion and gene targeting. Importantly, we observed that nat3Δ mutation partially suppressed MMS sensitivity in srs2Δ cells and the synthetic sickness of srs2Δ sgs1Δ cells. Altogether, our results indicate that NatB functions upstream of Srs2 to activate the Rad51-dependent HR pathway for DSB repair.

著者

Takashi Ohsako Machi Shirakami Kazuharu Oiwa Kimihide Ibaraki Timothy L. Karr Masatoshi Tomaru Rikako Sanuki Toshiyuki Takano-Shimizu-Kouno

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.21-00024, (Released:2021-09-24)

参考文献数

35

被引用文献数

3

---

Sperm are modified substantially in passing through both the male and the female reproductive tracts, only thereafter becoming functionally competent to fertilize eggs. Drosophila sperm become motile in the seminal vesicle; after ejaculation, they interact with seminal fluid proteins and undergo biochemical changes on their surface while they are stored in the female sperm storage organs. However, the molecular mechanisms underlying these maturation processes remain largely unknown. Here, we focused on Drosophila Neprilysin genes, which are the fly orthologs of the mouse Membrane metallo-endopeptidase-like 1 (Mmel1) gene. While Mmel1 knockout male mice have reduced fertility without abnormality in either testis morphology or sperm motility, there are inconsistent results regarding the association of any Neprilysin gene with male fertility in Drosophila. We examined the association of the Nep1–5 genes with male fertility by RNAi and found that Nep4 gene function is specifically required in germline cells. To investigate this in more detail, we induced mutations in the Nep4 gene by the CRISPR/Cas9 system and isolated two mutants, both of which were viable and female fertile, but male sterile. The mutant males had normal-looking testes and sperm; during copulation, sperm were transferred to females and stored in the seminal receptacle and paired spermathecae. However, following sperm transfer and storage, three defects were observed for Nep4 mutant sperm. First, sperm were quickly discarded by the females; second, the proportion of eggs fertilized was significantly lower for mutant sperm than for control sperm; and third, most eggs laid did not initiate development after sperm entry. Taking these observations together, we conclude that the Nep4 gene is essential for sperm function following sperm transfer to females.

著者

Takeru Tsunoi Koki Noju Takeshi Eto Hitoshi Suzuki

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.20-00049, (Released:2021-05-15)

参考文献数

63

---

The melanocortin-1 receptor gene (MC1R) controls production of the pigments eumelanin and pheomelanin. Changes in MC1R lead to variation in coat color in mammals, which can range from entirely black (melanism) to yellowish. In this study, we report a case of a wild-caught Norway rat (Rattus norvegicus) from Sado Island, Japan with a yellowish coat color. Upon sequencing the whole coding region of the Mc1r gene (954 bp), we found a 1-bp deletion at site 337 (c.337del), indicative of a frameshift mutation, which was characterized as a severe loss-of-function or null mutation. A spectrophotometer was used to measure coat color, revealing that the rat had a distinctly lighter coat, based on lightness score, than mice with homozygous similar loss-of-function mutations. This implies that loss-of-function mutations can yield different phenotypes in murine rodents. The loss-of-function-mutant rat exhibited a contrasting coat pattern consisting of darker and lighter colors along its dorsal and ventral sides, respectively. Similar patterns have been observed in homozygous MC1R-deficient mutants in other mammals, implying that the countershading pattern can still be expressed despite the absence of MC1R in the melanocyte.

著者

Wataru Sakamoto

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.78, no.1, pp.1-9, 2003 (Released:2003-03-18)

参考文献数

72

被引用文献数

67 90

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Leaf variegation has long been known as a recessive genetic trait in higher plants. Unlike albino mutants, leaf-variegated mutants are non-lethal and thus enable us to study a novel mechanism of plastid development and maintenance. Variegation results from a defect that makes chloroplast development unstable, since at least part of the tissues gives rise to normal chloroplasts. Despite the fact that leaf-variegated mutants have contributed to the findings of maternal inheritance or have been used as genetic markers, these mutations and the responsible loci have been poorly understood at the molecular level. A comprehensive study of the leaf-variegated mutants is possible in Arabidopsis, since such mutants have been known and the cloning can be at relative ease as a model plant. Here I summarize recent progress on characterization of the Arabidopsis leaf-variegated mutants. Detailed analysis of the responsible loci revealed that variegation is caused by a defect in various metabolic pathways related to organelle functions. Thus, studies on these genes provide us with novel redundant mechanisms by which heteroplasmic organelles such as plastids and mitochondria can survive from an environmental stress.

著者

Ikuo Miura Masataka Tagami Takeshi Fujitani Mitsuaki Ogata

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.92, no.4, pp.189-196, 2017-08-01 (Released:2018-02-10)

参考文献数

17

被引用文献数

1 6

---

The present study reports spontaneous tyrosinase gene mutations identified in oculocutaneous albinos of three Japanese wild frog species, Pelophylax nigromaculatus, Glandirana rugosa and Fejervarya kawamurai. This represents the first molecular analyses of albinic phenotypes in frogs. Albinos of P. nigromaculatus collected from two different populations were found to suffer from frameshift mutations. These mutations were caused by the insertion of a thymine residue within each of exons 1 and 4, while albinos in a third population lacked three nucleotides encoding lysine in exon 1. Albinos from the former two P. nigromaculatus populations were also associated with splicing variants of mRNA that lacked either exons 2–4 or exon 4. In the other two frog species examined, missense mutations that resulted in amino acid substitutions from glycine to arginine and glycine to aspartic acid were identified in exons 1 and 3, respectively. The two glycines in F. kawamurai and G. rugosa, and the lysine deleted in one P. nigromaculatus albino, were highly conserved in vertebrates, which suggested that they were situated in regions of critical importance to tyrosinase function. In fact, the glycine of G. rugosa is located within a predicted copper-binding domain. The five mutations identified in the present study are candidates for causing the albinic phenotypes, and, if directly confirmed, they are all unique among vertebrates, which suggests that molecular analysis of albino frogs could contribute to research on albinos in humans and vertebrates by providing new information about tyrosinase structure and transcript processing.

著者

Masayuki Horie

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.94, no.6, pp.253-267, 2019-12-01 (Released:2020-01-30)

参考文献数

89

被引用文献数

1 6

---

Riboviruses are viruses that have RNA genomes and replicate only via RNA intermediates. Although they do not require a DNA phase for replication and do not encode reverse transcriptase, the presence of DNA forms of riboviral sequences in ribovirus-infected cells has been reported since the 1970s. Additionally, heritable ribovirus-derived sequences, called riboviral endogenous viral elements (EVEs), have been found in the genomes of many eukaryotes. These are now thought to be formed by the reverse transcription machineries of retrotransposons within eukaryotic genomes sometimes referred to as selfish elements. Surprisingly, some reverse-transcribed riboviral DNAs (including EVEs) provide physiological functions for their hosts, suggesting the occurrence of novel interactions among eukaryotic genomes, retrotransposons and riboviruses, and opening the door to new avenues of investigation. Here I review current knowledge on these triangular interactions, and discuss future directions in this field.

著者

Uchu Yamakawa Shingo Kaneko Ryosuke Imai Leanne Kay Faulks Koetsu Kon Daisuke Kyogoku Yuji Isagi Yoshiaki Tsuda

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.19-00007, (Released:2019-11-16)

参考文献数

27

被引用文献数

2

---

The amphidromous sleeper Eleotris oxycephala (Perciformes: Eleotridae) is mainly distributed along the Kuroshio Current in East Asia, and this current is thought to be the main driver of the species' dispersal. Due to anthropogenic environmental changes in rivers, E. oxycephala is ranked as a threatened or near-threatened species in the red lists of 12 prefectures in Japan. Moreover, there is concern that the species' dispersal pattern could be changed due to fluctuations in the Kuroshio Current caused by global warming. In this study, 40 microsatellite markers were developed for E. oxycephala, and their suitability was tested on 43 individuals from two populations of E. oxycephala from Kanagawa and Miyazaki Prefectures. The number of alleles, expected heterozygosity and fixation index at each locus were 2–10 (mean = 5.350), 0.034–0.860 (mean = 0.650) and -0.261–0.448 (mean = 0.065), respectively. Furthermore, there was a lack of genetic difference between the two populations (FST = 0.008, F'ST = 0.024), indicating widespread gene flow via the Kuroshio Current. These markers will be useful to evaluate the genetic structure and infer population demographic history of E. oxycephala populations, which may assist in the conservation of this species.

著者

Kazuki Watanabe Yuki Suzuki Show Inami Hirono Ohashi Takaomi Sakai

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.18-00004, (Released:2018-07-11)

参考文献数

17

被引用文献数

3

---

In many animal species, females choose potential mating partners according to their own preferences. Thus, female preference-based mate choice affects intraspecific mating success and prevents interspecific mating. To clarify the neuronal basis of female mate choice, it is essential to identify the important relevant sensory cues. In the fruitfly Drosophila melanogaster, the courtship song of males promotes female sexual receptivity. When wild-type virgin females can freely choose one of two types of courting males (winged or wingless males), they prefer to mate with winged males. Here, we report a crucial sensory cue relevant to this female mate choice. In a female choice test, female receptivity toward winged and wingless males was markedly reduced when females had auditory impairments, although females with visual or olfactory impairments showed normal receptivity similar to wild-type females. However, females with visual impairments did not show clear mate preference toward winged males. Thus, these findings suggest that females utilize visual cues in mate choice between winged and wingless males in Drosophila.

著者

Naoyuki Nakahama Azusa Ito Shingo Kaneko Yu Matsuki Yoshihisa Suyama Azusa Hayano Miho Murayama Yuji Isagi

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.17-00021, (Released:2018-01-17)

被引用文献数

3

---

Microsatellite markers were developed for the endangered orchid Calanthe izu-insularis (Orchidaceae). This species is unique to the Izu Islands in Japan. Unfortunately, its population size has decreased because of excessive collection for horticultural purposes. In addition, although natural hybridization between C. izu-insularis and C. discolor var. discolor has been reported, morphological differences between C. izu-insularis and the hybridized individuals remain unclear. Using next-generation sequencing, 11 polymorphic microsatellite markers were developed. All developed markers could amplify C. aristulifera and nine markers could amplify C. d. var. discolor, two other orchid species that are also endangered in Japan. The number of alleles and expected heterozygosity at each locus were 1–6 (mean, 2.35) and 0.00–0.79 (mean, 0.30), respectively. These microsatellite markers will help conservation geneticists in their investigation of the proportion of pure C. izu-insularis individuals in the Izu Islands.

著者

Manuel Ruiz-García Pablo Orozco-terWengel Armando Castellanos Leonardo Arias

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.80, no.1, pp.57-69, 2005 (Released:2005-04-12)

参考文献数

55

被引用文献数

10 25

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DNA samples of the spectacled bear (Tremarctos ornatus) from five Andean countries, Venezuela, Colombia, Ecuador, Peru and Bolivia, were analyzed for nine microsatellite loci. Seven of them were polymorphic, which led us to investigate several population-genetic parameters. Private alleles and significant differences in gene frequencies were found among the populations studied, which demonstrated the extent of genetic differentiation among the spectacled bear populations. The levels of gene diversity measured with these microsatellites were rather modest in this species. Hardy-Weinberg disequilibrium was especially found for the overall and the Ecuadorian samples, and might be due to the Wahl-und effect or consanguinity. Significant genetic heterogeneity was mainly observed among the Colombian and the Ecuadorian populations. Markov chain Monte Carlo simulations clearly showed that two different gene pools were present, one present in the Venezuelan-Colombian bears and other in the Ecuadorian ones.

著者

Masaru Murakami Chikako Matsuba Hideo Fujitani

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.76, no.1, pp.25-32, 2001 (Released:2002-05-31)

参考文献数

23

被引用文献数

32 41

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The hyper-variable segments (323∼327 bp) of the mitochondrial D-loop for 169 Carassius auratus fishes in Japan were amplified by the polymerase chain reaction and the amplified products were sequenced directly and compared. A dendrogram showing three major clusters was generated with the sequence data for 37 haplotypes at 66 polymorphic sites. One cluster (cluster I) exclusively consisted of the gengorobuna, which was regarded as an independent (sub) species. The triploid ginbuna belonged to two remaining clusters, mainly in the diploid ginbuna cluster (cluster III) and partially in the goldfish cluster (cluster II). This finding suggests that the triploid ginbuna has been derived from two different maternal lineages. The triploid ginbuna was considered to have come into existence during the last ice age on the basis of this phylogenetic data. No geographic differentiation was observed with respect to the triploid ginbuna sampled at three different localities in Japan; the Shibuta River in Kanagawa, Lake Imba in Chiba and Lake Biwa in Shiga. The phylogenetic tree also demonstrated a monophyletic relationship amongst the nigorobuna, the nagabuna and the ginbuna, sharing cluster III. The nigorobuna and nagabuna populations have most likely arisen from geographic and temporal variations within the ginbuna populations. We also discuss the evolutionary origin of the triploid in view of its paternal ancestors.

著者

Jiro Osaka Haruka Yasuda Yusuke Watanuki Yuya Kato Yohei Nitta Atsushi Sugie Makoto Sato Takashi Suzuki

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.97, no.6, pp.297-309, 2022-12-01 (Released:2023-04-18)

参考文献数

35

被引用文献数

3

---

Neural activity-dependent synaptic plasticity is an important physiological phenomenon underlying environmental adaptation, memory and learning. However, its molecular basis, especially in presynaptic neurons, is not well understood. Previous studies have shown that the number of presynaptic active zones in the Drosophila melanogaster photoreceptor R8 is reversibly changed in an activity-dependent manner. During reversible synaptic changes, both synaptic disassembly and assembly processes were observed. Although we have established a paradigm for screening molecules involved in synaptic stability and several genes have been identified, genes involved in stimulus-dependent synaptic assembly are still elusive. Therefore, the aim of this study was to identify genes regulating stimulus-dependent synaptic assembly in Drosophila using an automated synapse quantification system. To this end, we performed RNAi screening against 300 memory-defective, synapse-related or transmembrane molecules in photoreceptor R8 neurons. Candidate genes were narrowed down to 27 genes in the first screen using presynaptic protein aggregation as a sign of synaptic disassembly. In the second screen, we directly quantified the decreasing synapse number using a GFP-tagged presynaptic protein marker. We utilized custom-made image analysis software, which automatically locates synapses and counts their number along individual R8 axons, and identified cirl as a candidate gene responsible for synaptic assembly. Finally, we present a new model of stimulus-dependent synaptic assembly through the interaction of cirl and its possible ligand, ten-a. This study demonstrates the feasibility of using the automated synapse quantification system to explore activity-dependent synaptic plasticity in Drosophila R8 photoreceptors in order to identify molecules involved in stimulus-dependent synaptic assembly.

著者

Nobuyuki Inomata Manami Miyazaki Mayu Noguchi Masanobu Itoh

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.97, no.5, pp.221-227, 2022-10-01 (Released:2023-02-22)

参考文献数

30

---

Physiological responses to environmental changes play important roles in adaptive evolution. In particular, homeostatic regulatory systems that maintain constant circulating glucose levels are crucial in animals. However, variation in circulating glucose levels and the genetic effects on phenotypic variation in natural populations remain to be clarified. Here, we investigated the hemolymph glucose levels in natural populations of Drosophila melanogaster and its sibling species, D. simulans, in Japan. We quantified hemolymph glucose concentrations in third instar larvae of 27 lines for each species, which were reared on either glucose-free or glucose-rich food. In both species, genetic variation was not a major component of phenotypic variation on either glucose-free or glucose-rich food. The hemolymph glucose concentrations were much higher in D. simulans than in D. melanogaster. Genetic variance was larger in D. simulans than in D. melanogaster. The observed differences between the two species may be associated with the much more recent colonization history of D. simulans populations in Japan and/or the tolerance to environmental stresses. Our findings suggest that natural selection acting on hemolymph glucose levels in D. melanogaster is different from that in D. simulans.

著者

Hanna Nishida Takuya Suzaki

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

pp.22-00104, (Released:2023-01-11)

参考文献数

18

被引用文献数

2

---

Root nodule symbiosis is promoted in nitrogen-deficient environments, whereas host plants cease the symbiosis if they can obtain enough nitrogen from their surrounding soil. In Lotus japonicus, recent reports indicate that two NODULE INCEPTION (NIN)-LIKE PROTEIN (NLP) transcription factors, LjNLP1 and LjNLP4, play important roles in the regulation of gene expression and nodulation in response to nitrate. To characterize the redundant and unique roles of LjNLP1 and LjNLP4 in more detail, we reanalyzed our previous transcriptome data using Ljnlp1 and Ljnlp4 mutants. Although downstream genes of LjNLP1 and LjNLP4 mostly overlapped, we found that nitrate-induced expression of NITRATE TRANSPORTER 2 (LjNRT2) family genes was specifically regulated by LjNLP1. In contrast, LjNRT1 gene family expression was regulated by both LjNLP1 and LjNLP4. Therefore, it is likely that the two NLPs play distinct roles in the regulation of nitrate transport.

著者

Jun Kitano Seiichi Mori

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.91, no.2, pp.77-84, 2016-04-01 (Released:2016-10-13)

参考文献数

78

被引用文献数

9

---

Stickleback fishes have been established as a leading model system for studying the genetic mechanisms that underlie naturally occurring phenotypic diversification. Because of the tremendous diversification achieved by stickleback species in various environments, different geographical populations have unique phenotypes and genotypes, which provide us with unique opportunities for evolutionary genetic research. Among sticklebacks, Japanese species have several unique characteristics that have not been found in other populations. The sympatric marine threespine stickleback species Gasterosteus aculeatus and G. nipponicus (Japan Sea stickleback) are a good system for speciation research. Gasterosteus nipponicus also has several unique characteristics, such as neo-sex chromosomes and courtship behaviors, that differ from those of G. aculeatus. Several freshwater populations derived from G. aculeatus (Hariyo threespine stickleback) inhabit spring-fed ponds and streams in central Honshu and exhibit year-round reproduction, which has never been observed in other stickleback populations. Four species of ninespine stickleback, including Pungitius tymensis and the freshwater, brackish water and Omono types of the P. pungitius-P. sinensis complex, are also excellent model systems for speciation research. Anthropogenic alteration of environments, however, has exposed several Japanese stickleback populations to the risk of extinction and has actually led to extinction of several populations and species. Pungitius kaibarae, which is endemic to East Asia, used to inhabit Kyoto and Hyogo prefectures, but is now extinct. Causes of extinction include depletion of spring water, landfill of habitats, and construction of river-mouth weirs. Here, we review the importance of Japanese sticklebacks as genetic resources, the status of several endangered stickleback populations and species, and the factors putting these populations at risk.

著者

Yukihide Abe Atsushi Hoshino Shigeru Iida

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.72, no.2, pp.57-62, 1997 (Released:2002-12-03)

参考文献数

22

被引用文献数

7 13

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The speckled mutant of the Japanese morning glory blooms pale yellow flowers with fine and round colored spots, or speckles, distributed over the corolla. Since it also occasionally produces flowers with colored sectors apparently due to somatic mutations, the mutable speckled allele is thought to carry a transposable element. In this paper, we show that the appearance of the variegation phenotypes in the speckled mutant was controlled not only by the recessive speckled allele but also by a dominant genetic element, termed speckled-activator. Our results also indicated that the recessive c-1 mutation affecting pigmentation of flowers and mapped near the speckled locus causes a defect in a regulatory gene controlling the expression of structural genes for anthocyanin biosynthesis.

著者

Yoshiyuki Suzuki

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.85, no.6, pp.359-376, 2010 (Released:2011-03-11)

参考文献数

172

被引用文献数

20 29

---

In the study of molecular and phenotypic evolution, understanding the relative importance of random genetic drift and positive selection as the mechanisms for driving divergences between populations and maintaining polymorphisms within populations has been a central issue. A variety of statistical methods has been developed for detecting natural selection operating at the amino acid and nucleotide sequence levels. These methods may be largely classified into those aimed at detecting recurrent and/or recent/ongoing natural selection by utilizing the divergence and/or polymorphism data. Using these methods, pervasive positive selection has been identified for protein-coding and non-coding sequences in the genomic analysis of some organisms. However, many of these methods have been criticized by using computer simulation and real data analysis to produce excessive false-positives and to be sensitive to various disturbing factors. Importantly, some of these methods have been invalidated experimentally. These facts indicate that many of the statistical methods for detecting natural selection are unreliable. In addition, the signals that have been believed as the evidence for fixations of advantageous mutations due to positive selection may also be interpreted as the evidence for fixations of deleterious mutations due to random genetic drift. The genomic diversity data are rapidly accumulating in various organisms, and detection of natural selection may play a critical role for clarifying the relative role of random genetic drift and positive selection in molecular and phenotypic evolution. It is therefore important to develop reliable statistical methods that are unbiased as well as robust against various disturbing factors, for inferring natural selection.

著者

Yasuko Kato Akiko Sawada Kazuki Tonai Hisashi Tatsuno Takahisa Uenoyama Masanobu Itoh

出版者

The Genetics Society of Japan

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.96, no.6, pp.259-269, 2021-12-01 (Released:2022-04-21)

参考文献数

55

被引用文献数

1

---

A spontaneous mutation, enNK14, was a new allele of engrailed (en) in Drosophila melanogaster. Females of enNK14 have three spermathecae, instead of two in wild type, under a wide range of developmental temperatures, while the males show no abnormal phenotype. Spermathecae of the mutant female can accept inseminated sperms, albeit with a delay of at least an hour until full acceptance compared with wild type. The time course of decrease in the number of stored sperms was thoroughly similar between the mutant and wild type. enNK14 females produced fewer progeny than wild type females despite storing a larger number of sperms. The delay of sperm entry and lower fecundity suggested some functional defects in secretory products of the spermathecae. In addition, some spermathecae in the mutant were accompanied by a mass of brown pigments in the adipose tissue surrounding the capsule. Six contiguous amino acids, Ser340–Ala345, were replaced by one Thr in enNK14. In another mutant, enspt, Ser325 was also shown to be substituted by a Cys. These amino acid changes were located within a serine-rich region, in which Ser325, Ser340 and Thr341 were suggested as targets of Protein Kinase C by an in silico analysis. The splicing pattern of en mRNA did not differ between enNK14 and wild type in embryo, larva, pupa or adult. Our results suggest that en plays an important role in determining the number of spermathecae as well as in sperm storage function in the Drosophila female.