ホッカイドウ ワシュ バ ニ オケル カスゲ ホモ ガタ コタイ ノ チシ セツ ニ カンスル ツイカ ブンセキ

北海道和種馬において,粕毛のホモ型個体は生存するという結果を報告したが,その分析に一部不備があったのでさらに解析を加えた。その結果,粕毛(R)とその遺伝子頻度は,R/R型個体の生存説に従って算出した頻度に合致した。また交配組み合わせの確率から求めた子馬集団における粕毛と非粕毛個体の出現はホモ型生存説に従って分離していた。In order to test whether or not homozygotes (R/R) of the roan gene (R) existed in the population of Hokkaido native horses, a statistical-genetic analysis was carried out. Proportion of roan to non-roan foals expected to appear from mating combinations were computed separately in the R/R survival and lethal theory. The observation fitted with the former theory. This conclusion is the same as that of the previous report

The Low-Velocity, Rapidly Fading Type Ia Supernova 2002es

SN 2002es is a peculiar subluminous Type Ia supernova (SN Ia) with a combination of observed characteristics never before seen in a SN Ia. At maximum light, SN 2002es shares spectroscopic properties with the underluminous SN 1991bg subclass of SNe Ia, but with substantially lower expansion velocities (~6000 km/s) more typical of the SN 2002cx subclass. Photometrically, SN 2002es differs from both SN 1991bg-like and SN 2002cx-like supernovae. Although at maximum light it is subluminous (M_B=-17.78 mag), SN 2002es has a relatively broad light curve (Dm15(B)=1.28 +/- 0.04 mag), making it a significant outlier in the light-curve width vs. luminosity relationship. We estimate a 56Ni mass of 0.17 +/- 0.05 M_sun synthesized in the explosion, relatively low for a SN Ia. One month after maximum light, we find an unexpected plummet in the bolometric luminosity. The late-time decay of the light curves is inconsistent with our estimated 56Ni mass, indicating that either the light curve was not completely powered by 56Ni decay or the ejecta became optically thin to gamma-rays within a month after maximum light. The host galaxy is classified as an S0 galaxy with little to no star formation, indicating the progenitor of SN 2002es is likely from an old stellar population. We also present a less extensive dataset for SN 1999bh, an object which shares similar observed properties. Both objects were found as part of the Lick Observatory Supernova Search, allowing us to estimate that these objects should account for ~2.5% of SNe Ia within a fixed volume. We find that current theoretical models are unable to explain the observed of characteristics of SN 2002es.Comment: 19 pages, 15 figures, Submitted to Ap

Modified differentials and basic cohomology for Riemannian foliations

We define a new version of the exterior derivative on the basic forms of a Riemannian foliation to obtain a new form of basic cohomology that satisfies Poincar\'e duality in the transversally orientable case. We use this twisted basic cohomology to show relationships between curvature, tautness, and vanishing of the basic Euler characteristic and basic signature.Comment: 20 pages, references added, minor corrections mad

ホッカイドウ ワシュバ ニ オケル カスゲ ノ ホモイデンシガタ ワ チシ デ ナイ

ウマの毛色遺伝のうち粕毛ホモ接合体(R/R型)は致死であると言われているが,北海道和種馬で粕毛は高頻度で出現し,R/R型のホモ型個体が生存している可能性が高いとされている。そこで,その正否を明らかにするため,粕毛の遺伝様式について独自の調査を行った。北海道和種馬における粕毛の出現頻度は0.507と全体の約半分を占めていた。両親または片親に粕毛を持つ個体間の交配資料を用いてχ^2検定を行った結果,粕毛×粕毛の交配において,ホモ型致死説では子ウマにおける粕毛と非粕毛の分離比は理論値と一致せず(p<0.001),ホモ型生存説では分離比と理論値が一致した(p=0.2～0.1)。また,粕毛×非粕毛の交配では統計学的にホモ型致死説を否定できなかったが,ホモ型生存説による分離比の方がより理論値と一致した。この交配例では子ウマにおける粕毛と非粕毛の分離比が1.3 : 1の時に,統計学的に最も高い確率で適合した。さらに,血統登録種牡馬においてホモ型粕毛個体の推定を行った結果,17頭のうち3頭のホモ型個体の存在が推定された。以上のことから,北海道和種馬における粕毛ホモ型個体は生存している可能性が確認された。The roan gene affects coat color heredity in horses. Though it is said that the roan gene homozygte (R/R type) carries lethality, the roan appears with high frequency among Hokkaido native horses, and there is a high possibility for individuals with R/R type to exist. Therefore, an original investigation was carried out to clarify the heredity mode of the roan. The frequency of the roan Hokkaido native horse was about 0.507. As a result of χ^2 test using the mating material between individual horses with either roan parents or one parent, in the mating of roan × roan, the separation ratio agreed with the theoretical value of the separation ratio of roan and non-roan in the foals based on the homozygote survival theory(p=0.2～0.1), and did not agree with the theoretical value in the homozygote lethality theory (p<0.001). In the mating of roan × non-roan, though the homozygote lethality theory was not statistically denied, it was not well supported, while the theoretical separation ratio based on the homozygote survival theory agreed with the actual value. In this mating example, the separation ratio of roan and non-roan among the foals with the statistically highest probability was 1.3 : 1 (p=0.9～0.8). In addition, the existence of a homozygote individual was predicted, and the three homozygote animals were observed among 17 roan stallion horses which had many foals and were booked in the pedigree registration. From the above facts, it was confirmed that there were homozygote roans among Hokkaido native horses

Refining the evolutionary tree of the horse Y chromosome

The Y chromosome carries information about the demography of paternal lineages, and thus, can prove invaluable for retracing both the evolutionary trajectory of wild animals and the breeding history of domesticates. In horses, the Y chromosome shows a limited, but highly informative, sequence diversity, supporting the increasing breeding influence of Oriental lineages during the last 1500 years. Here, we augment the primary horse Y-phylogeny, which is currently mainly based on modern horse breeds of economic interest, with haplotypes (HT) segregating in remote horse populations around the world. We analyze target enriched sequencing data of 5 Mb of the Y chromosome from 76 domestic males, together with 89 whole genome sequenced domestic males and five Przewalski's horses from previous studies. The resulting phylogeny comprises 153 HTs defined by 2966 variants and offers unprecedented resolution into the history of horse paternal lineages. It reveals the presence of a remarkable number of previously unknown haplogroups in Mongolian horses and insular populations. Phylogenetic placement of HTs retrieved from 163 archaeological specimens further indicates that most of the present-day Y-chromosomal variation evolved after the domestication process that started around 4200 years ago in the Western Eurasian steppes. Our comprehensive phylogeny significantly reduces ascertainment bias and constitutes a robust evolutionary framework for analyzing horse population dynamics and diversity

CRISPR Inhibition of Prophage Acquisition in Streptococcus pyogenes

Streptococcus pyogenes, one of the major human pathogens, is a unique species since it has acquired diverse strain-specific virulence properties mainly through the acquisition of streptococcal prophages. In addition, S. pyogenes possesses clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems that can restrict horizontal gene transfer (HGT) including phage insertion. Therefore, it was of interest to examine the relationship between CRISPR and acquisition of prophages in S. pyogenes. Although two distinct CRISPR loci were found in S. pyogenes, some strains lacked CRISPR and these strains possess significantly more prophages than CRISPR harboring strains. We also found that the number of spacers of S. pyogenes CRISPR was less than for other streptococci. The demonstrated spacer contents, however, suggested that the CRISPR appear to limit phage insertions. In addition, we found a significant inverse correlation between the number of spacers and prophages in S. pyogenes. It was therefore suggested that S. pyogenes CRISPR have permitted phage insertion by lacking its own spacers. Interestingly, in two closely related S. pyogenes strains (SSI-1 and MGAS315), CRISPR activity appeared to be impaired following the insertion of phage genomes into the repeat sequences. Detailed analysis of this prophage insertion site suggested that MGAS315 is the ancestral strain of SSI-1. As a result of analysis of 35 additional streptococcal genomes, it was suggested that the influences of the CRISPR on the phage insertion vary among species even within the same genus. Our results suggested that limitations in CRISPR content could explain the characteristic acquisition of prophages and might contribute to strain-specific pathogenesis in S. pyogenes

Characterization of a heat-activated retrotransposon in Vigna angularis

In plants, several transposable elements are conserved across species. We found a homolog of ONSEN, which is a heat-activated retrotransposon originally isolated from Arabidopsis thaliana, in Vigna. The ONSEN-like elements (VaONS) were detected in all the analyzed Japanese accessions of Vigna angularis (adzuki bean) by Southern blot analysis. However, VaONS sequences were observed to be polymorphic in the different accessions. Interestingly, extrachromosomal DNA (ecDNA) was detected in some accessions of adzuki bean, indicating the conserved heat-activation of VaONS. Furthermore, we successfully induced retrotransposition of VaONS in adzuki plant regenerated through callus. Findings of our study should provide a new tool for molecular breeding of adzuki bean