Recombination suppression at the dominant <Emphasis Type="Italic">Rhg1/Rfs2</Emphasis> locus underlying soybean resistance to the cyst nematode

Host resistance to “yellow dwarf” or “moonlight” disease cause by any population (Hg type) of Heterodera glycines I., the soybean cyst nematode (SCN), requires a functional allele at rhg1. The host resistance encoded appears to mimic an apoptotic response in the giant cells formed at the nematode feeding site about 24–48 h after nematode feeding commences. Little is known about how the host response to infection is mediated but a linked set of 3 genes has been identified within the rhg1 locus. This study aimed to identify the role of the genes within the locus that includes a receptor-like kinase (RLK), a laccase and an ion antiporter. Used were near isogeneic lines (NILs) that contrasted at their rhg1 alleles, gene-based markers, and a new Hg type 0 and new recombination events. A syntenic gene cluster on Lg B1 was found. The effectiveness of SNP probes from the RLK for distinguishing homolog sequence variants on LgB1 from alleles at the rhg1 locus on LgG was shown. The resistant allele of the rhg1 locus was shown to be dominant in NILs. None of the recombination events were within the cluster of the three candidate genes. Finally, rhg1 was shown to reduce the plant root development. A model for rhg1 as a dominant multi-gene resistance locus based on the developmental control was inferred.     

Recessive allelic variations of three microsatellite sites within the<Emphasis Type="Italic">O2</Emphasis> gene in maize

Recessive allelic variations were investigated at 3 microsatellite (SSR) sites within theO2 gene by using 14 inbredo2 lines and a wild-type line in maize. Among the 15 lines, allelic variations were observed at umc1066, phi057, and phi112 sites. Two alleles were found at the umc1066 site—a recessive allele with 2 perfect GCCAGA repeats and a dominant allele with 3 perfect repeats. Three alleles were found at the phi057 site—2 recessive alleles with 3 and 5 perfect GCC repeats, respectively, and another with 4 perfect repeats consistent with a dominant allele. At least 4 alleles exist at the phi112 site—among which 1 recessive allele has a 1-bp deletion, another has a 15-bp deletion, and other has no PCR products compared to the dominant allele; all the alleles have unchanged AG repeats. The phi057 site in exon 6 was identified to be a hypervariable region in the coding sequence of the02 gene, in addition to the 2 hypervariable regions in exon 1 previously reported. The primary mechanisms underlying the variations in repeat numbers and regions flanking the SSR within theO2 gene appear to be unequal crossing over and replication slippage. Furthermore, base substitution of SSR motif can create heteroalleles and modify the repeat number of SSR. The lysine content of kernel in theO2 ando2 lines correlates to a considerable extent with nucleotide variations at the umc1066, phi057, and phi112 sites. Our study suggests that it is best to use the 3 markers together in molecular marker-assisted selection for high-lysine maize materials.     

Haplotypic Diversity Within the Ovine Calpastatin <Emphasis Type="Italic">(CAST)</Emphasis> Gene

Calpastatin (CAST) is a protein inhibitor that acts specifically on calpains and plays a regulatory role in postmortem beef tenderization and muscle proteolysis. Polymorphisms in the bovine CAST gene have been associated with meat tenderness, but little is known about how the ovine CAST gene may affect sheep meat quality traits. In this study, we selected two parts of the ovine CAST gene that have been previously reported to be polymorphic (region 1—part of intron 5 and exon 6, and region 2—part of intron 12), to investigate haplotype diversity across an extended region of the ovine gene. First, we developed a simple and efficient polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) method for genotyping region 2, which allowed the detection of a novel allele as well as the three previously reported alleles. Next, we genotyped both regions 1 and 2 of the ovine CAST gene from a large number of sheep to determine the haplotypes present. Nine different haplotypes were found across this extended region of the ovine CAST gene and four haplotypes were identified that suggested historical recombination events within this gene. Haplotypes are typically more informative than single nucleotide polymorphisms (SNPs) for analyzing associations between genes and complex production traits, such as meat tenderness, but the potential for intragenic recombination within the ovine CAST may make finding associations challenging.     

Structural feature of sorghum chloroplast psbA gene and regulation effects of its 5'-noncoding region*

Comparative analysis reveals remarkahle homology between the sequences of bothpsbA gene nucleotides and the inferred amino acids of sorghum, a C₄ plant, and those of rice, a C₃ plant. The 5′-noncoding region of sorghumpsbA gene contains the conservative promoter elements, “—35” element and “—10” element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using anin vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically hinds to the 5′-noncoding region ofpsbA gene. Measurement of the expression of luciferase shows a 2–5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghumpsbA gene than that of the expression plasmids pALqr which contain leader region of ricepsbA gene inE. coli. Project supported by the Chinese National “863” and “973” Projects     

Subtropical coral-reef associated sedimentary facies characterized by molluscs (Northern Bay of Safaga, Red Sea, Egypt)

Summary The shallow marine subtropical Northern Bay of Safaga is composed of a complex pattern of sedimentary facies that are generally rich in molluscs. Thirteen divertaken bulk-samples from various sites (reef slopes, sand between coral patches, muddy sand, mud, sandy seagrass, muddy seagrass, mangrove channel) at water depths ranging from shallow subtidal to 40m were investigated with regard to their mollusc fauna >1mm, which was separated into fragments and whole individuals. Fragments make up more than 88% of the total mollusc remains of the samples, and their proportions correspond to characteristics of the sedimentary facies. The whole individuals were differentiated into 622 taxa. The most common taxon,Rissoina cerithiiformis, represented more than 5% of the total mollusc content in the samples. The main part of the fauna consists of micromolluscs, including both small adults and juveniles. Based on the results of cluster-, correspondence-, and factor analyses the fauna was grouped into several associations, each characterizing a sedimentary facies: (1) “Rhinoclavis sordidula—Corbula erythraeensis-Pseudominolia nedyma association” characterizes mud. (2) “Microcirce sp.—Leptomyaria sp. association” characterizes muddy sand. (3)”Smaragdia spp.-Perrinia stellata—Anachis exilis—assemblage” characterizes sandy seagrass. (4) “Crenella striatissima—Rastafaria calypso—Cardiates-assemblage” characterizes muddy seagrass. (5) “Glycymeris spp.-Parvicardium sueziensis-Diala spp.-assemblage” characterizes sand between coral patches. (6) “Rissoina spp.-Triphoridae —Ostreoidea-assemblage” characterizes reef slopes. (7) “Potamides conicus—Siphonaria sp. 2—assemblage” characterizes the mangrove. The seagrass fauna is related to those of sand between coral patches and reef slopes with respect to gastropod assemblages, numbers of taxa and diversity indices, and to the muddy sand fauna on the basis of bivalve assemblages and feeding strategies of bivalves. The mangrove assemblage is related to those of sand between coral patches and the reef slope with respect to taxonomic composition and feeding strategies of bivalves, but has a strong relationship to those of the fine-grained sediments when considering diversity indices. Reef slope assemblages are closely related to that of sand between coral patches in all respects, except life habits of bivalves, which distincly separates the reef slope facies from all others.     

Efficient generation of long-distance conditional alleles using recombineering and a dual selection strategy in replicate plates

Background  

Conditional knockout mice are a useful tool to study the function of gene products in a tissue-specific or inducible manner. Classical approaches to generate targeting vectors for conditional alleles are often limited by the availability of suitable restriction sites. Furthermore, plasmid-based targeting vectors can only cover a few kB of DNA which precludes the generation of targeting vectors where the two loxP sites are placed far apart. These limitations have been overcome in the recent past by using homologous recombination of bacterial artificial chromosomes (BACs) in Escherichia coli to produce large targeting vector containing two different loxP-flanked selection cassettes so that a single targeting event is sufficient to introduce loxP-sites a great distances into the mouse genome. However, the final targeted allele should be free of selection cassettes and screening for correct removal of selection cassettes can be a laborious task. Therefore, we developed a new strategy to rapidly identify ES cells containing the desired allele.     

Two novel gene mutations (Glu174→Lys,Phe383→Tyr) causing the “hepatic” form of carnitine palmitoyltransferase II deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency has two different clinical forms, one with “hepatic” and the other with “muscular” symptoms. We studied the molecular basis of the “hepatic” form in two Japanese siblings. Their CPT II activity in lymphoblasts was reduced to 3% of the level observed in normal controls. cDNA analysis showed that the proband was a compound heterozygote. One allele carried a new mutation, G621→A (Glu174→Lys). The other carried three single-base substitutions; a new mutation, T1249→A (Phe383→Tyr), and two previously reported polymorphisms. The brother had the same four substitutions. Neither of the two new mutations in this study was detected in the 60 alleles of 30 Japanese control subjects. Secondary structure prediction analysis of the mutated CPT II protein was different from that of the normal protein. We concluded that these mutations caused the “hepatic” form of CPT II deficiency in the probands. Received: 16 October 1995     

Role of SNAP25 Explored in Eastern Indian Attention Deficit Hyperactivity Disorder Probands

Synaptosomal-associated protein 25 (SNAP25) is an essential component for synaptic vesicle mediated release of neurotransmitters. Deficiencies or abnormal structure or function of SNAP25 protein, possibly arising through genetic variations in the relevant DNA code, has been suggested to play role in the pathology of several neurobehavioural disorders including Attention deficit Hyperactivity Disorder (ADHD) and a number of polymorphisms in the SNAP25 gene has been studied for association with the disorder. In the present investigation, for the first time association between ADHD and six SNAP25 polymorphisms, rs1889189, rs362569, rs362988, rs3746544, rs1051312, and rs8636 was explored in eastern Indian population. Subjects were recruited following the Diagnostic and Statistical Manual for Mental Disorders-IV. Genomic DNA isolated from peripheral blood leukocytes of ADHD probands (n = 150), their parents (n = 272) and ethnically matched controls (n = 100) was used for amplifying target sites. Data obtained were subjected to population- as well as family-based analyses. While case–control analysis revealed lack of any significant difference for alleles, family-based studies revealed a mild over transmission rs3746544 ‘T’ and rs8636 ‘C’ alleles (P = 0.05 and 0.03 respectively). Haplotypes formed between rs362569 “T”, 362988 “G”, rs3746544 “T”, rs1051312 “T” and rs8636 “C” in different combinations showed statistically significant transmission to ADHD probands. Excepting rs3746544 and rs8636, all the tested sites showed very low linkage disequilibrium between them. Data obtained in this preliminary study indicates that rs3746544 ‘T’ allele may have some role in the disease etiology in the studied Indian population.     

Polymorphism of transferrin found in the laboratory rat and wild rats in Japan

Polymorphism of the transferrin locus (Tf) was found in the laboratory rat and wild rats in Japan by polyacrylamide gel electrophoresis. Two phenotypes, “a” and “b,” were distinguished in homozygotes. It is suggested that these are controlled by autosomal codominant alleles. In 10 laboratory strains, only the IS strain showed the a type. This allele found in the IS strain was broadly distributed in Japanese wild rats. It is considered to be derived from a wild rat in Japan. Linkage relationship betweenTf andAlp-1 was not established.     

Conservation in wheat high-molecular-weight glutenin gene promoter sequences: comparisons among loci and among alleles of the GLU-B1-1 locus

 The high-molecular-weight glutenin (HMW) genes and encoded subunits are known to be critical for wheat quality characteristics and are among the best-studied cereal research subjects. Two lines of experiments were undertaken to further understand the structure and high expression levels of the HMW-glutenin gene promoters. Cross hybridizations of clones of the paralogous x-type and y-type HMW-glutenin genes to a complete set of six genes from a single cultivar showed that each type hybridizes best within that type. The extent of hybridization was relatively restricted to the coding and immediate flanking DNA sequences. Additional DNA sequences were determined for four published members of the HMW-glutenin gene family (encoding subunits Ax2^*, Bx7, Dx5, and Dy10) and showed that the flanking DNA of the examined genes diverge at approximately −1200 bp 5′ to the start codon and 200–400 bp 3′ to the stop codon. These divergence sites may indicate the boundaries of sequences important in gene expression. In addition, promoter sequences were determined for alleles of the Bx gene (Glu-B1-1), a gene reported to show higher levels of expression than other HMW-glutenin genes and with variation among cultivars. The sequences of Bx promoters from three cultivars and one wild tetraploid wheat indicated that all Bx alleles had few differences and contained a duplicated portion of the promoter sequence “cereal-box” previously suspected as a factor in higher levels of expression. Thus, the “cereal-box” duplication preceeded the origin of hexaploid wheat, and provides no evidence to explain the variations in Bx subunit synthesis levels. One active Bx allele contained a 185-bp insertion that evidently resulted from a transposition event. Received: 5 August 1997 / Accepted: 6 November 1997     

Sibling rivalry between seeds within a fruit: Some population genetic models

Competition between seeds within a fruit for parental resources is described using one-locus-two-allele models. While a “normal” allele leads to an equitable distribution of resources between seeds (a situation which also corresponds to the parental optimum), the “selfish” allele is assumed to cause the seed carrying it to usurp a higher proportion of the resources. The outcome of competition between “selfish” alleles is also assumed to lead to an asymmetric distribution of resources, the “winner” being chosen randomly. Conditions for the spread of an initially rare selfish allele and the optimal resource allocation corresponding to the evolutionarily stable strategy, derived for species with n-seeded fruits, are in accordance with expectations based on Hamilton’s inclusive fitness criteria. Competition between seeds is seen to be most intense when there are only two seeds, and decreases with increasing number of seeds, suggesting that two-seeded fruits would be rarer than one-seeded or many-seeded ones. Available data from a large number of plant species are consistent with this prediction of the model. Based on a talk given at the Haldane Centenary Symposium held on 6 November 1992 at Ahmedabad as part of the 58th Annual Meeting of the Indian Academy of Sciences.     

Evolution of introns and exons of class II major histocompatibility complex genes of vertebrates

 The phylogenetic relationships and patterns of nucleotide substitution were compared for introns and exons of class II major histocompatibility complex (MHC) genes in three datasets: human DRB1, human DQA1, and cyprinid fish DAB1. In both human DRB1 and cyprinid DAB1, there was strong evidence that recombination events between alleles have occurred in such a way that intron and exon sequences of a given allele do not necessarily share the same evolutionary history. In the case of human DRB1, recombination was found to have homogenized intron 1 and intron 2 sequences relative to exon 2 sequences within lineages of alleles but not between lineages. As a result, mean divergence times of intron sequences are much more recent than those of exonic sequences. Thus, the divergence time of DRB1 introns cannot be used to date that of exons in the same alleles, and the hypothesis that most human DRB1 polymorphism is of very recent origin is not supported. Received: 5 September 1999 / Revised: 30 December 1999     

Conditional gene knockout using cre recombinase

Cre recombinase has become an important instrument for achieving precise genetic manipulation in mice. Many of these desired genetic manipulations rely on Cre’s ability to direct spatially and temporally specified excision of a predesignated DNA sequence that has been flanked by directly repeated copies of the loxP recombination site. Success in achieving such conditional mutagenesis in mice depends both on the careful design of conditional alleles and on reliable detection of cre gene expression. These procedures include PCR, immunohistochemistry and the use of a recombination-proficient GFP-tagged Cre protein.     

The basis for haplotype complexity in VCBPs, an immune-type receptor in amphioxus

Innate immune gene repertoires are restricted primarily to germline variation. Adaptive immunity, by comparison, relies on somatic variation of germline-encoded genes to generate extraordinarily large numbers of non-heritable antigen recognition motifs. Invertebrates lack the key features of vertebrate adaptive immunity, but have evolved a variety of alternative mechanisms to successfully protect the integrity of “self”; in many cases, these appear to be taxon-specific innovations. In the protochordate Branchiostoma floridae (amphioxus), the variable region-containing chitin-binding proteins (VCBPs) constitute a multigene family (comprised of VCBPs 1–5), which possesses features that are consistent with innate immune-type function. A large number of VCBP alleles and haplotypes are shown to exhibit levels of polymorphism exceeding the elevated overall levels determined for the whole amphioxus genome (JGI). VCBP genes of the 2 and 5 types are distinguished further by a highly polymorphic segment (exon 2) in the N-terminal immunoglobulin domain, defined previously as a “hypervariable region” or a “hotspot.” Genomic deoxyribonucleic acid (DNA) and complementary DNA (cDNA) sequences from large numbers of animals representing different populations reveal further significant differences in sequence complexity within and across VCBP2/5 haplotypes that arise through overlapping mechanisms of genetic exchange, gene copy number variation as well as mutation and give rise to distinct allelic lineages. The collective observations suggest that mechanisms were in place at the time of divergence of the cephalochordates that could selectively hyperdiversify immune-type receptors within a multigene family.     

Structural feature of sorghum chloroplastpsbA gene and regulation effects of its 5′-noncoding region

Comparative analysis reveals remarkahle homology between the sequences of bothpsbA gene nucleotides and the inferred amino acids of sorghum, a C₄ plant, and those of rice, a C₃ plant. The 5′-noncoding region of sorghumpsbA gene contains the conservative promoter elements, “—35” element and “—10” element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using anin vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically hinds to the 5′-noncoding region ofpsbA gene. Measurement of the expression of luciferase shows a 2–5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghumpsbA gene than that of the expression plasmids pALqr which contain leader region of ricepsbA gene inE. coli.     

Generation of a mouse for conditional excision of progesterone receptor

The progesterone receptor (PR) is required for several aspects of mammalian female reproduction. PR null mice have overlapping defects that preclude an understanding of its multiple functions in ovulation, pregnancy, mammary gland biology, and sexual behavior. We have generated a PR conditional excision (PRCE) allele in which loxP sites flank exon 1. Homozygous PRCE females are fertile and appear to be functionally normal. Global cre mediated excision of the floxed exon 1 using EIIa-cre mice resulted in systemic loss of exon 1 and PR protein. Female mice homozygous for this null allele were sterile, as expected for PR knockout (PRKO) females. Conditional loss of PR will facilitate investigation of the spatial and temporal roles of PR in both normal development and disease.     

Art in global context: An evolutionary/functionalist perspective for the 21<Superscript>st</Superscript> century

Regarding the arts as something peopledo — as behaviors, rather than the residue or artifacts of behavior — makes possible a theoretical grounding about their nature and importance, an endeavor that current anthropology of art has largely abandoned. A reconsideration of the suspect and largely discarded terms “functionalism” and “evolutionism” is presented in light of current evolutionary thinking. It is suggested that a contemporary reformulation of these concepts, illustrated by the author's Darwinian or “adaptationist” perspective on art, supports aims and claims of current anthropology of art, and contributes new focus and direction to its endeavors.     

Molecular characterization of the Himalayan mink

A rare color variant of the American mink (Neovison vison), discovered on a ranch in Nova Scotia and referred to as the “marbled” variety, carries a distinctive pigment distribution pattern resembling that found in some other species, e.g., the Siamese cat and the Himalayan mouse. We tested the hypothesis that the color pattern in question—light-colored body with dark-colored points (ears, face, tail, and feet)—is due to a mutation in the melanin-producing enzyme tyrosinase (TYR) that results in temperature-sensitive pigment production. Our study shows that marbled mink carry a mutation in exon 4 of the TYR gene (c.1835C > G) which results in an amino acid substitution (p.H420Q). The location of this substitution corresponds to the amino acid position that is also mutated in the TYR protein of the Himalayan mouse. Thus, the marbled variant is more aptly referred to as the Himalayan mink.     

A reexamination of Gilligan’s analysis of the female moral system

Gilligan’s (1982) refinement of Kohlberg’s theory on moral development operates on two theses: (1) females, more so than males, reach moral decisions based on the personalities of the relevant individuals; and (2) female behaviors stemming from moral decisions are based upon “care” and “responsibility for others.” This article accepts the first thesis but argues that the second is incorrect. That is, self-interest—i.e., aiding “blood” kin and/or carefully monitoring reciprocity—rather than “altruism” is argued to be the operant dynamic in forging distaff morality and resultant behavior. Six empirical examples are presented as contraindicative of Gilligan’s second thesis. Finally, it is suggested that selection for the psychological traits of independence and the mastery of subtle social chess yielded ancestral females who had more descendants—us—than did females with alternative profiles. Nancy S. Coney is a professor at Western Illinois University and is interested in both clinical and nonclinical aspects of women’s psychology. Wade C. Mackey is interested in biocultural anthropology and has authored two books on fathering:Fathering Behaviors (Plenum, 1995) andThe American Father (Plenum, 1996).