Purification of Primordial Germ Cells from TNAPMouse Embryos Using FACS-gal

Tissue nonspecific alkaline phosphatase (TNAP), the product of theAkp2locus, is expressed in mouse primordial germ cells (PGC) for an extensive period during embryogenesis. Mice with theAkp2^tm1Sormutant allele of TNAP expresslacZ(β-galactosidase; β-gal) under control of theAkp2locus. PGCs were purified fromAkp2^tm1Sorembryos using fluorescence activated cell sorting of β-gal expressing cells (FACS-gal). Analysis of the purified cells by alkaline phosphatase staining and immunocytochemistry with anti-c-kitantibody demonstrated that highly (98%) purified PGCs can be isolated using this method. This technique will facilitate experiments that require highly purified preparations of PGCs including cell culture and gene expression analyses.     

Serological identification of sperm antigens specified by lethalt-alleles in the mouse

Cytotoxic antisera were prepared by immunizing wild-type recipient mice with sperm from donors carrying different recessive lethal alleles at theT locus (T/t ⁰,T/t ^{w 1} ,T/t ^{w 5} , andT/t ^{w 32} ). After removal of sperm autoantibody by absorption with sperm of recipient type, each antiserum reacted only with sperm from males whose genotype contained at least one of the immunizing alleles. Cytotoxicity was high against sperm populations in which both immunizing alleles were represented and was lower when only one was present. Thus, each allele at theT locus which has so far been tested serologically is recognizable as a discrete antigen on the surface of sperm.This paper is dedicated to Professor Hans Grüneberg, F.R.S. on the occasion of his retirement from the chair of Animal Genetics at University College London, in appreciation of the fact that it was he who first suggested that surface properties played an important role in the origin of abnormalities associated with mutants at theT-locus.     

Genetics of rye phosphatases: evidence of a duplication

Summary Genetic analyses were conducted on alkaline phosphatases of the endosperm of dry kernels and leaf acid phosphatases in four open pollinated and one inbred line of cultivated rye (Secale cereale L.). A total of seven alkaline phosphatase isozymes were observed occurring at variable frequencies in the different cultivars analyzed. We propose that at least five loci control the alkaline phosphatases of rye endosperm — Alph-1, Alph-2, Alph-3, Alph-4 and Alph-5 — all of which have monomeric behaviour. The leaf acid phosphatases are controlled by one locus and have a dimeric quaternary structure. All loci coding for alkaline phosphatase isozymes showed one active, dominant allele and one null, recessive allele, except for the locus Alph-3 which showed two active, dominant alleles and one null, recessive one. The linkage analyses suggest the existence of two linkage groups for alkaline phosphatases: one of them would contain Alph-2, Alph-4, Alph-5 and the locus/loci coding isozymes 6 and 7. This linkage group is located in the 7RS chromosome arm. The other group would include Alph-1 and Alph-3 loci, being located in the 1RL chromosome arm. Leaf acid phosphatases have been previously located in the 7RL chromosome arm. Our data also support an independent relationship between loci controlling the endosperm alkaline phosphatases and leaf acid phosphatases.     

Storage-protein variation in wild emmer wheat (Triticum turgidum ssp.dicoccoides) from Jordan and Turkey. I. Electrophoretic characterization of genotypes

Seed storage-protein variation at theGlu-A1,Glu-B1 andGli-B1/Glu-B3 loci in the tetraploid wild progenitor of wheat,T. dicoccoides, was studied electrophoretically in 315 individuals representing nine populations from Jordan and three from Turkey. A total of 44 different HMW-glutenin patterns were identified, resulting from the combination of 15 alleles in the A genome and 19 in the B genome. Twenty-seven new allelic variants, 12 at theGlu-A1 locus and 15 at theGlu-B1 locus, were identified by comparing the mobilities of their subunits to those previously found in bread and durum wheats. The novel variants include six alleles at theGlu-A1 locus showing both x and y subunits. The genes coding for the 1Bx and 1By subunits showed no or very little (3%) inactivity, the 1Ax gene showed a moderate degree (6.3%) of inactivity whereas the gene coding for lAy showed the highest degree of inactivity (84.8%). A high level of polymorphism was also present for the omega- and gamma-gliadins and LMW-glutenin subunits encoded by genes at the linkedGli-B1 andGlu-B3 loci (19 alleles). Some Jordanian accessions were found to contain omega-gliadin 35, gamma-gliadin 45, and LMW-2 also present in cultivated durum wheats and related to good gluten viscoelasticity. The newly-discovered alleles enhance the genetic variability available for improving the technological quality of wheats. Additionally some of them may facilitate basic research on the relationship between industrial properties and the number and functionality of HMW- and LMW-glutenin subunits.     

Genetic factors affecting allelic recombination at the histidine-3 locus ofNeurospora crassa

Summary In addition to the generec-4, other genetic factors affect the frequency of allelic recombination in thehis-3 locus. One dominant factor, designated asrec-6 ⁺, in association withrec-4 ⁺ causes greater reduction in prototrophic frequency than obtained withrec-4 ⁺ alone. The action ofrec 6 ⁺ in crosses recessive homozygous forrec-4 is not established at the present. The effect ofrec-6 ⁺ is recognised only with onehis-3 allele but not with another. Interaction ofrec-4 ⁺ orrec-4 with other genetic factors can give approximately ten fold variation in the prototrophic frequencies obtained with a pair of alleles. It is suggested that the control of the rate of mutations during meiosis might be one of the roles of the recombination genes.     

Direct determination of usual (Caucasian-type) and atypical (Oriental-type) alleles of the class I human alcohol dehydrogenase-2 locus

Two types of alleles exist in the human alcohol dehydrogenase-2 (ADH ₂) locus. The usualADH ₂ ¹ allele is common in Caucasians, while the atypicalADH ₂ ² allele is predominant in Orientals. TheADH ₂ ² produces the β₂ subunit, which is catalytically far more active than the β₁ subunit produced by theADH ₂ ¹ gene. The racial difference in alcohol-related problems could be related to the genetic differences in ADH and other ethanol-metabolizing enzymes. In order to examine the possibility, a method for determiningADH ₂ genotypes was developed. Two 21-base synthetic oligonucleotides, one complementary to the usualADH ₂ ¹ allele and the other complementary to the atypicalADH ₂ ² allele, were used as specific probes for in-gel hybridization analysis of human genomic DNA from peripheral blood. Under appropriate hybridization conditions, these two probes can hybridize to their specific complementary alleles and, thus, allow the genotyping of theADH ₂ locus. Genotypes of theADH ₂ locus of 49 unrelated Japanese individuals were determined. The frequency of the atypicalADH ₂ ² gene was found to be 0.71 in the Japanese population examined. This research was supported by Grant AA05763 from the National Institutes of Health.     

TheD17Tu5 locus in thet complex: implications for the origin oft haplotypes and inbred strains

The mouse × Chinese hamster cell line R4 4-1 contains only one mouse chromosome, the bulk of which corresponds toMus musculus chromosomes 17 and 18 (MMU17 and MMU18, respectively). A genomic library was prepared from the R4 4-1 DNA, and a mouse clone was isolated from the library, which—with the help of somatic cell hybrids-could be mapped to the MMU17. A locus defined by a 2.7-kb longBam HI probe from this clone was designatedD17Tu5 (Tu for Tübingen). The locus proved to be polymorphic among inbred strains and wild mice. By testing of recombinant inbred strains and partialt haplotypes, theD17Tu5 locus could be mapped to a position between theD17Leh66E andD17Rp17 loci within thet complex. Two alleles were found at this locus,D17Tu5 ^a andD17Tu5 ^b , defined byTaq I restriction fragment length polymorphism. Both alleles are present among inbred strains and wild mice of the speciesM. domesticus. All completet haplotypes tested carry theD17Tu5 ^a allele and all tested wild mice of the speciesM. musculus, with the exception of those bearingt haplotypes, carry theD17Tu5 ^b allele. Additional alleles are found in some populations of wild mice and in other species of the genusMus. The distribution of the two alleles among the inbred strains correlates well with their known or postulated genealogy. Their distribution between the two species ofMus and among the mice withT haplotypes suggests a relatively recent origin of thet haplotypes.     

Mapping of theHox-3.1 andMyc-1.2 genes on chromosome 15 of the mouse by restriction fragment length variations

Restriction endonuclease fragment length variations (RFLV) were detected by use of the cDNA probeHox-3.1 for the homeo box-3.1 gene and also thec-myc oncogene probe for exon 2. RFLV ofHox-3.1 were found inHindIII restriction patterns, and RFLV of theMyc-1.2 gene inEcoRV patterns. From the RFLV, theHox-3.1 andMyc-1.2 genes were mapped on chromosome 15. Three-point cross test data showed that the frequency of recombination is 26.4% betweenMyc-1.2 andGpt-1, 30.2% betweenGpt-1 andGdc-1, and 9.4% betweenGdc-1 andHox-3.1. The following order of these genes is proposed,Myc-1.2—Gpt-1—Gdc-1—Hox-3.1. All laboratory strains carry theHox-3.1 ^a andMyc-1.2 ^a alleles. Among strains of wild origin,domesticus strains carry only theHox-3.1 ^a andMyc-1.2 ^a alleles, as do the laboratory strains. One strain ofbrevirostris carries theHox-3.1 ^a andMyc-1.2 ^b alleles. Other wild subspecies from Europe and Asia,M. m. musculus, M. m. castaneus, M. m. molossinus, Chinese mice of wild origin, andM. m. yamashinai carry theHox-3.1 ^b andMyc-1.2 ^b alleles.     

Chromosomal location of the gene encoding the murine acute-phase protein serum amyloid P-component (SAP)

A full-length cDNA clone, pmSAP3, encoding the serum P component (SAP), has been used to search for DNA fragment length variation among mouse strains previously analyzed for differences in endogenous SAP levels. Three alleles were found usingEcoRI-digested DNA. The finding of a single 5.4-kb fragment, alleled, in DNA from DBA/2J mice suggests the presence of a singleSap locus. Segregation of DNA fragment associated withSap ^b andSap ^d alleles was analyzed in three sets of recombinant inbred (RI) strains. The strain distribution pattern found for theSap alleles was identical to that of alleles ofLy-9 in 43 individual RI strains, suggesting tight linkage withLy-9 on mouse chromosome 1. In the BXD RI strains, the SDP of theSap locus, defined by the difference in the endogenous SAP level, is also identical to the SDP of the DNA fragments. We propose to redesignate theSap locus to include both the structural element defined by the DNA polymorphism and the regulatory element involved in the regulation of SAP synthesis. TheSap locus is the major genetic element contributing to the regulation of SAP production. Other genetic factors are also involved, as shown by the presence of nonparental phenotypes in the individual BXH RI strains. This study was performed through special Coordination Funds of the Science and Technology Agency of the Japanese Government and PHS Grant GM24464 to R.W.E.     

Plant color effects of certain anomalous forms of theRrallele in maize

Summary The genetically changes forms ofR ^r arising regularly in maize plants heterozygous for the stippled, light stippled, and marbled alleles, and previously shown to influence aleurone color differentially, were found to affect coleoptile and seedling leaf sheath color also. Failure to demonstrate corresponding differential effects on root pigmentation possibly was due to inadequacy of the testing procedure. Two of the modified forms ofR ^r were observed to reduce glume and anther color also. The experimental results imply that theR locus as a region is involved in the phenomenon.Paper No. 677 from the Department of Genetics, College of Agriculture, University of Wisconsin.     

Role ofS gene product of bacteriophage lambda in host cell lysis

Studies with the induced lysogens of λS ⁺R⁺, λS^-R⁺, λS⁺R^- and λS-R^- phages have shown that while theS gene product is essential for the action of intracellularR gene product to release the periplasmic alkaline phosphatase in the presence of EDTA, the latter gene product can bring about this effect while acting onEscherichia coli cells from outside, in the absence of functionalS gene product; chloroform, could help the intracellularR gene product in effecting bacterial lysis in the absence ofS gene product. These result support the premise that theS gene product facilitates theR gene product in crossing the cytoplasmic membrane into the periplasmic space such that the latter can act on the peptidoglycan layer of the host cell thus causing both the release of alkaline phosphatase and cell lysis. An erratum to this article is available at .     

Variability and genetics of spacer DNA sequences between the ribosomal-RNA genes of hexaploid wheat (Triticum aestivum)

Summary Using restriction enzyme digests of genomic DNA extracted from the leaves of 25 hexaploid wheat (Triticum aestivum L. em. Thell.) cultivars and their hybrids, restriction fragment length polymorphisms of the spacer DNA which separates the ribosomal-RNA genes have been examined. (From one to three thousand of these genes are borne on chromosomes 1B and 6B of hexaploid wheat). The data show that there are three distinct alleles of the 1B locus, designated Nor-B1a, Nor-B1b, and Nor-B1c, and at least five allelic variants of the 6B locus, designated Nor-B2a, Nor-B2b, Nor-B2c, Nor-B2d, and Nor-B2e. A further, previously reported allele on 6B has been named Nor-B2f. Chromosome 5D has only one allelic variant, Nor-D3. Whereas the major spacer variants of the 1B alleles apparently differ by the loss or gain of one or two of the 133 bp sub-repeat units within the spacer DNA, the 6B allelic variants show major differences in their compositions and lengths. This may be related to the greater number of rDNA repeat units at this locus. The practical implications of these differences and their application to wheat breeding are discussed.     

Recombination at the Rp1 locus of maize.

Summary The Rp1 locus of maize determines resistance to races of the maize rust fungus (Puccinia sorghi). Restriction fragment length polymorphism markers that closely flank Rp1 were mapped and used to study the genetic fine structure and role of recombination in the instability of this locus. Susceptible progeny, lacking the resistance of either parent, were obtained from test cross progeny of several Rp1 heterozygotes. These susceptible progeny usually had non-parental genotypes at flanking marker loci, thereby verifying their recombinational origin. Seven of eight Rp1 alleles (or genes) studied were clustered within about 0.2 map units of each other. Rpl ^G, however, mapped from 1–3 map units distal to other Rp1 alleles. Rp5 also mapped distally to most Rp1 alleles. Other aspects of recombination at Rp1 suggested that some alleles carry duplicated sequences, that mispairing can occur, and that unequal crossing-over may be a common phenomenon in this region; susceptible progeny from an Rp1 ^A homozygote had recombinant flanking marker genotypes, and susceptible progeny from an Rp1 ^DlRp1 ^F heterozygote showed both possible nonparental flanking marker genotypes.     

Phosphoglucomutase electrophoretic variants in the mouse

The phosphoglucomutase (PGM) electrophoretic phenotype of the mouse (Mus musculus) consists of several distinct components which can be grouped into two major zones designated PGM-1 and PGM-2. Evidence presented here indicates that each zone is controlled by a single genetic locus denoted Pgm-1 and Pgm-2, respectively. Two variant forms segregated at the Pgm-1 locus. They were codominantly expressed and inherited as alleles at an autosomal locus. The alleles were termed Pgm-1 ^a (fast) and Pgm-1 ^b (slow). These alleles were separately fixed in a number of inbred strains of mice. Preliminary evidence based on wild mouse phenotypes indicates that variant forms also exist for PGM-2 which are inherited as alleles at an autosomal locus. Genetic linkage relationships have not been determined for these loci. PGM-1 variants and PGM-2 were expressed in mouse fibroblasts in vitro.Supported by U.S. Public Health Service grants GM-09966 and GM-07249 from General Medical Sciences and 5 F2 HD-35,531 from Child Health and Human Development; and Atomic Energy Commission contract AT(30-1)-3671.Postdoctoral Fellow of the U.S. Public Health Service.     

Recombination rates of soybean varieties from different periods of introduction and release

Theory predicts that selection for adaptability during the short term also favors selection for a reduced recombination rate in the population. The objective of this study was to test whether the cyclic short-term selection which has taken place in soybean breeding programs in the USA since the introduction of the crop has measurably reduced recombination frequencies. Thirteen soybean varieties separated into four different release periods (prior to 1940, 1940–1954, 1955–1969, after 1970) were evaluated for their recombination frequencies within three locus pairs. Recombination frequencies among the individual varieties ranged from 7.6 to 24.1 % at thep ₁ r locus pair, from 20.9 to 30.1 % at thelnp ₂ locus pair, and from 28.7 to 41.6% at thedt ₁ l ₁ locus pair. Recombination frequencies were significantly different among varieties within a release period for thep ₁ r andlnp ₂ locus pairs, but recombination frequencies did not differ among release periods for any locus pair. Thus, apparently, plant breeders have developed soybean varieties with improved adaptation without influencing recombination rates.     

Evolutionary conservation of linkage groups: Additional evidence from murid and cricetid rodents

In Mus musculus, family Muridae, the glucosephosphate isomerase (Gpi-1), pink-eyed dilution (p), albinism (c), and -type globin (Hbb) loci are known to be linked in the order Gpi-1-p-c-Hbb. In Rattus norvegicus, another murid rodent, the p, c, and Hbb loci are known to be linked in the same order and with similar recombination frequencies. In Peromyscus maniculatus, family Cricetidae, it was previously known that p and c are linked and by analogy to Mus musculus that linkage group should be bounded by Gpi-1 near p and by a -globin locus near c. Linkage has now been established between Gpi-1 and the Hbe globin locus in Peromyscus. However, the observed recombination frequency in Peromyscus (16.3%) is significantly lower than in Mus, suggesting that perhaps a chromosomal inversion has occurred during the evolutionary divergence of the two rodent families. Linkage relationships were also tested between the Hbc ¹, Hbd ¹, and Hbe ¹ globin variants. Hbc ¹ (presumably an -type globin) segregated independently from Hbd ¹ and Hbe ¹ (presumably -type globins). No recombination was observed between Hbd ¹ and Hbe ¹. Those two globin genes may be alleles at a single locus, although circumstantial evidence suggests that they represent tightly linked duplicate loci.This work was supported by NSF DEB7716104 and by the Committee on Research, UCR.     

TheRT1.G locus in the rat encodes a Qa/TL-like antigen

A new antigenic system in the rat homologous to theQa/TL antigen system in the mouse has been characterized. It was detected by antibodies raised in donor-recipient combinations that were matched for theRT1. A, B, D, E loci in the major histocompatibility complex (MHC): (R11×BN)F₁ anti-BN.1L(LEW), (R18×BN)F₁ anti-BN.1L, and BN.1LV1(F344) anti-BN.1L. Absorption analyses using these antisera and a variety of inbred, congenic and recombinant strains identified three alleles,RT1.G ^a ,G ^b ,G ^c , of whichG ^c is a null allele. The strain distribution of these alleles was determined, using 37 strains of rats representative of all of the prototypic haplotypes and a number of congenic and recombinant strains. The use of the congenic and recombinant strains showed that theRT1.G locus was linked to the MHC and that the most probable gene order wasA-E-G. Testcross analysis showed that the map distance betweenA andG was 1.4 cM(4/285 recombinants). The RT1.G antigen has a heavy chain ofM _r 46 000 and is present on both T and B cells.     

Time of Recombination in the DROSOPHILA MELANOGASTER Oocyte. III. Selection and Characterization of Temperature-Sensitive and -Insensitive, Recombination-Deficient Alleles in Drosophila

The procedure for the selection of a temperature-sensitive recombination mutant in Drosophila is described. Use of this procedure has led to the recovery of three alleles at a new recombination locus called rec-1, located within the region of chromosome 3 circumscribed by Deficiency (3R)sbd¹⁰⁵. One allele, rec-1²⁶, is temperature sensitive, and the other two alleles, rec-1⁶ and rec-1¹⁶, are temperature insensitive. Gene dosage studies reveal rec-1²⁶ to be a leaky mutant with greater recombination activity in two doses than in one. The other two alleles show no dose response, implying that they may be null mutants. The temperature response curves of rec-1²⁶ as a homozygote and in heteroallelic combination with rec-1¹⁶ suggest that the sharp decrease in recombination between 28° and 31° indicates temperature denaturation of an enzyme or other protein specified by the mutant and associated with the recombination process. The ability of small changes in temperature to reverse or abolish polarity in recombination along the X chromosome arm in rec-1 ²⁶/rec-1¹⁶ females brings into question the use of the "polarity" criterion to partition mutants into two functional types, i.e., precondition mutants that display polarity and exchange mutants that do not. Evidence that rec-1 may be part of a complex locus residing in a chromosome segment harboring a variety of recombination-related genes is presented.     

Developmental genetic analysis of lethal alleles at the ewg locus and their effects on muscle development in Drosophila melanogaster

The recessive X-linked mutation erect wing (ewg), in Drosophila melanogaster, was characterized as a flightless behavioral mutant which specifically lacked the dorsal longitudinal flight muscles [1]. This mutation was mapped distal to the X chromosomal locus yellow, and further to the cytological segment 1 A 1 to 1 B2-3 [2]. Several lethal complementation groups have been mapped to this interval [3]. Our complementation tests show that ewg is allelic to one lethal complementation group in the region 1 A 1 to 1 B2-3. A further analysis of ewg and several lethal alleles isolated at this locus was undertaken in the present investigation. Most of the lethal alleles at this locus lead to a late embryonic or early larval lethal phase, indicating that the ewg⁺ gene product is necessary for the development of more than just the dorsal longitudinal flight muscles. Intragenic complementation was observed for some of the ewg lethal alleles. Genetic mosaics with ewg lethal alleles showed that mutant cell clones in cuticular structures are viable. Mosaic analysis is consistent with a mesodermal defect associated with the locus.     

Typing forHLA-DPB1 * 03 andHLA-DPB1 * 06 using allele-specific DNA in vitro amplification and allele-specific oligonucleotide probes. Detection of “new” DPB1*06 variants

DP gene typing using in vitro DNA amplification combined with sequence-specific oligonucleotide probes has recently been reported. The resulting DNA amplification was specific for theHLA-DPB locus. Typing for the individualDPB alleles was exclusively dependent on the hybridizations of the probes but hampered by close sequence homology between differentDP alleles yielding complex patterns of reactivity with a panel of probes. We report the combined use of allele-specific DNA in vitro amplification and allele-specific oligonucleotides in typing forDPB1 ^* 03 andDPB1 ^* 06. Complete concordance with PLT typing was observed for theDPB1 ^* 03 alleles, while in the DPB1^*06 group, at least three variantDPB1 ^* 06 alleles were identified which have not been described previously.