Genetic Linkage Between Isozyme, Morphological, and DNA Markers in Tepary Bean

A genetic map of tepary bean (Phaseolus acutitolius A. Gray) may be useful to plant breeders attempting to transfer desirable genes from this species to other Phaseolus species. In order to expand the genetic information available for tepary bean, the inheritance of and linkage relationships among 23 morphological, isozyme, and RFLP markers were determined. All but one of the characters segregated in a monogenic fashion, and low levels of segregation distortion were observed. New two-locus linkages Identified included Aat-2/Gpi-c2, Aco-2/Dia-3, and Dia-3/ldh-x. Nine of the 23 loci exhibited linkage to other loci analyzed and could be assigned to one of three district linkage groups. Two tepary bean linkage groups (Adh-1/Aat-2, Aco-2/Dia-3) appear to be conserved in common bean, although the linkage estimates for Adh-1Aat-2 are dramatically different in these species. The Adh-1/Aat-2 linkage also appears to be conserved in lentil and pea. Additionally, the Gpi-c1/Pgd-3 linkage has a possible counterpart in soybean, and the Fdh-1/Gpi-c1 linkage in tepary bean is maintained In chickpe

Investigations of an urban area and its locale using ERTS-1 data supported by U-photography

An urban area in central Pennsylvania and the surrounding locality were investigated separately at first by photointerpretation of ERTS-1 imagery and by computer processing of MSS tapes. Next the photointerpretation and processing were coordinated. The results of the cooperative effort of photointerpreters and computer processing analysts were much improved over independent efforts. It was found that single frames of U-2 photography could be projected onto printer output maps with little recognizable distortion in areas 10 to 25 cm square. In this way targets could be identified for use as training areas for computer processed signature identification. In addition, at any stage of category mapping, the level of success in correct classification could be assessed by this method. The results of the classification of the study area are discussed

A Marker Locus, Adh-1, for Resistance to Pea Enation Mosaic Virus in Pisum sativum

Linkage between Adh-1, the locus specifying the more anoda) isozyme of alcohol dehydrogenase, and En, the locus controlling resistance to pea enation mosaic virus, was investigated in the garden pea, Pisum sativum L. A recombination frequency of 4% was observed between the two loci, indicating that Adh-1 may be a practical marker for En. The use of Adh-1 in combination with other loci as brackets around En, thereby increasing the reliability of an indirect screen, is also discusse

Chromosomal locations of twelve isozyme loci in Pisum sativum

Approximate chromosomal locations of 12 loci specifying electrophoretic enzyme variants are described in the garden pea (Pisum sativum L.). The enzyme loci are distributed on five of the seven chromosomes. The position of the loci on chromosomes 2 and 3 are such that most of the known markers on these chromosomes will exhibit linkage with at least one of the isozyme loci. Several of the loci studied code for enzymes that have isozymic counterparts in other compartments of the cell. In order to distinguish among the genes coding these isozymes we have added a suffix to the locus designation corresponding to the intracellular location of its produc

Extensive Conservation of Linkage Relationships Between Pea and Lentil Genetic Maps

A 560-cM linkage map consisting of 64 morphological, isozyme, and DNA markers, has been developed from an interspecific cross (Lens ervoides × L. Culinaris). In addition, nine markers were scored that assorted independently of any of the multilocus linkage groups. Comparison of this map with that established previously for Pisum sativum reveals eight regions in which linkages among marker loci appear to have been conserved since the divergence of the two genera. These conserved linkage groups constitute at least 250 cM, or approximately 40% of the known linkage map for Lens. The two genera represent disparate lineages within the legume tribe Vicease, indicating that all members of this tribe may possess linkage groups similar to those identified in Lens and Pisum. Instances where the Pisum and Lens maps differed included the regions surrounding the 45S ribosomal tandem repeats and the position and distribution of the genes encoding the small subunit of ribulose bisphosphate carboxylase. We also found a highly repeated sequence unique to Lens that maps within a linkage group shared between the two genera and a cDNA sequence that displays significant variation in copy number within the genus Len

Inheritance and Linkage Relationships of Morphological and Isozyme Loci in Lentil (Lens Miller)

Allozyme polymorphisms for 18 loci are described and their monogenic inheritance is demonstrated. We investigated linkage relationships among the 18 isozyme loci as well as four genes controlling morphological traits. Six small linkage groups were identified, containing 14 of the loci analyzed. Several of these groups appear to be conserved between Lens and Pisum, indicating that this intergeneric comparison may expedite genetic studies and breeding programs in both crop

An isozyme marker for resistance to bean yellow mosaic virus in Pisum sativum

Linkage between Pgm-p, the locus specifying the plastid specific phosphoglucomutase, and Mo, the locus controlling resistance to bean yellow mosaic virus (BYMV), was investigated in the garden pea, Pisum sativum L. Both genes are known to be on chromosome 2 and exhibit linkage with two morphological marker loci, K and Wb. Our results indicate that the gene order is: Wb—K—Pgm-p—Mo. A map distance of approximately two recombinant units was determined for the Pgm-p—Mo linkage, suggesting that the enzyme locus can be used as a genetic marker for resistance to BYM

Chromosomal Location of Lectin Genes Indicates They Are Not the Basis of Rhizobium Strain Specificity Mutations Identified in Pea (Pisum sativum L.)

A lectin gene family is located on linkage group 7 in pea. The lectin genes are arranged as a cluster, with no recombination observed within the multigene family. A lectinlike cDNA clone, pEA207, and eight DNA fragments generated by random priming also were mapped in the region of the lectin genes. None of the known pea mutants altering Rhizobium leguminosarum strain specificity map to this region of the genome, and therefore their altered specificities appear not to be directly produced by mutations in the lectin gene

Non-nodulating Mutants of Pisum Sativum (L.) cv. Sparkle

Eleven pea mutants, displaying a greatly reduced number of root nodules or lacking such nodules completely, were obtained by screening the M2 progeny of mutagenized Pisum sativum cv. Sparkle. The mutant alleles conditioning the altered nodulation phenotypes were recessive to the wild-type alleles. Eight of the mutants possessed a normal growth habit except for the complete lack of nodules. Pairwise crosses among these mutants indicated that five distinct loci had been affected. The remaining three mutants formed few nodules and also had altered root or shoot growth habit. Each of these plejotropic mutants was coded by a distinct gene. The eight genes identified are designated sym7, sym8, sym9, sym10, sym11, sym15, sym16, and sym17, signifying their involvement in the pea/Rhizobium symbiosis. The locations of most of these sym genes were determined by classical linkage mapping. The loci were distributed on at least five of the seven chromosome

Duplication of Aldolase and Esterase Loci in Cicer (Cicereae Alef.)

The genetic control of fructose bisphosphate aldolase (ALDO, EC 4.1.2.13) and esterase (EST, EC 3.1.1.2) isozymes in Cicer was studied by starch gel electrophoresis. Fixed heterozygote enzyme phenotypes were observed in homozygous lines for both Aldo-1, Aldo-2 and Est-4, Est-5. Crosses between the individuals carrying different alleles of the duplicated genes gave rise to asymmetrically staining bands for both enzyme systems. Subcellular localization studies demonstrated that the products of duplicated aldolase loci are present in the plastids, whereas duplicated esterase isozymes were found in the cytosolic compartment. Selfing and crossing experiments revealed that there are two nuclear genes encoding the plastid specific ALDO isozymes (Aldo-1 and Aldo-2). Similarly, EST-4 and EST-5 isozymes are specified by two nuclear genes (Est-4 and Est-5). No linkage was found between any of the duplicated genes and the other isozyme loci examined in this study. Taxonomic distribution of both duplications was examined in the electrophoretic survey of the related species. Present evidence suggests that these duplications are unique and probably occurred only in this monophyletic tribe, Cicereae, since no duplication was reported in the related genera. No evidence for mutations silencing any of the duplicated copies was detected in the genus. Although the mechanism for duplications is not known, evidence for translocations in Cicer and the existence of a similar linkage between ALDO and EST isozymes in related genera indicate that both duplications may have arisen simultaneously via duplication of a chromosomal segment carrying the ancestral state of the gene