Genetic mapping and manipulation: Chapter 2-Two-point mapping with genetic markers

ABSTRACT Through use of tetrad, random spore, trisomic, and mitotic analysis procedures a large number of genes, including 48 new genetic markers, were studied for their locations on the genetic maps of the yeast Saccharomyces cerevisiae. Eighteen new centromere linked genes were discovered and all but one was located on various ones of the 16 previously-established chromosomes. Five fragments of linked genes were also assigned to chromosomes; four were located on known chromosomes while the fifth determined one arm of a new chromosome. The experiments indicate that seventeen is likely to be the haploid chromosome number in this yeast. Most chromosomes have been established by genetic means to be metacentric and their genetic lengths vary from 5 cM to approximately 400 cM. Functionally-related sets of genes generally were found to be dispersed over the genome.

Download Full-text

CONGRESSION OF UNLINKED MARKERS AND GENETIC MAPPING IN THE TRANSFORMATION OF BACILLUS SUBTILIS 168

Genetics ◽

10.1093/genetics/73.1.13 ◽

1973 ◽

Vol 73 (1) ◽

pp. 13-21

Author(s):

Robert J Erickson ◽

James C Copeland

Keyword(s):

Bacillus Subtilis ◽

Genetic Mapping ◽

Genetic Markers ◽

Competent Cell ◽

Dna Molecules ◽

Bacillus Subtilis 168

ABSTRACT A thorough examination of cotransformation of two unlinked genetic markers in Bacillus subtilis 168 shows that the two recombinational events do not occur randomly. The cotransformation frequency is dependent on the distance between the two markers as well as on the order in which they replicate in the competent cell. These results indicate that uptake and/or integration of DNA molecules bearing these genetic markers is enhanced at the time these markers replicate in the competent cell.

Download Full-text

GENETIC MAPPING IN SCHIZOSACCHAROMYCES POMBE BY MITOTIC AND MEIOTIC ANALYSIS AND INDUCED HAPLOIDIZATION

Genetics ◽

10.1093/genetics/87.3.471 ◽

1977 ◽

Vol 87 (3) ◽

pp. 471-489 ◽

Cited By ~ 3

Author(s):

Jürg Kohli ◽

Herbert Hottinger ◽

Peter Munz ◽

Andre Strauss ◽

Pierre Thuriaux

Keyword(s):

Chromosome Number ◽

Genetic Mapping ◽

Schizosaccharomyces Pombe ◽

Fission Yeast ◽

Genetic Markers ◽

Genetic Maps ◽

Deficient Mutant ◽

Linkage Groups ◽

Meiotic Analysis ◽

Haploid Chromosome Number

ABSTRACT The genetic maps of the fission yeast Schizosaccharomyces pombe were extended through the use of haploidization (spontaneous or induced by m-fluorophenylalanine), as well as by tetrad, random spore and mitotic analysis. A new diploidization method utilizing a meiosis-deficient mutant and improved haploidization techniques was employed. As a result of these and previous studies, 118 genetic markers have been assigned to 3 linkage groups. Centromere markers for all 3 chromosomes were identified and genetic maps containing a total of 71 genes were constructed. Our experiments indicate that 3 is very likely to be the haploid chromosome number of S. pombe.

Download Full-text

Mitotic mapping ofSchizosaccharomyces pombe

Genetics Research ◽

10.1017/s0016672300002366 ◽

1970 ◽

Vol 16 (2) ◽

pp. 127-144 ◽

Cited By ~ 22

Author(s):

Miguel Flores da Cunha

Keyword(s):

Genetic Mapping ◽

Fission Yeast ◽

Genetic Markers ◽

Mechanism Of Action ◽

Genetic Identification ◽

Crossing Over ◽

Cell Divisions ◽

Progressive Loss ◽

Diploid Cells ◽

Linkage Relationships

SUMMARYGenetic mapping by means of mitotic haploidization (induced by parafluoropkenylalanine) and mitotic crossing-over was carried out with the fission yeastSchizosaccharomyces pombe. Thirty-two different genetic markers were involved in this investigation; some meiotic linkage relationships had been previously reported (Leupold, Megnet) for 16 of these loci. Mitotic haploidization experiments resulted in the genetic identification of six chromosomes in the haploid complement.Furthermore, in an attempt to study the mechanism of action of parafluorophenylalanine (pFPA) on mitotic haploidization, pedigree analyses were performed by micromanipulation of diploid cells growing in the presence of pFPA. Haploid cells were detected after 40 hours of contact with the analogue and many lethal pedigree branches were observed. These observations seem to agree with Käfer's (1961) and Lhoa's (1968) suggestion that mitotic haploidization in Fungi is achieved by progressive loss of chromosomes throughout cell divisions.

Download Full-text

Genetic Mapping in Autohexaploid Sweet Potato with Low-coverage NGS-based Genotyping Data

10.1101/789198 ◽

2019 ◽

Author(s):

Eiji Yamamoto ◽

Kenta Shirasawa ◽

Takumi Kimura ◽

Yuki Monden ◽

Masaru Tanaka ◽

...

Keyword(s):

Genetic Mapping ◽

Sweet Potato ◽

Genetic Markers ◽

Cost Effective ◽

Read Depth ◽

Sequencing Data ◽

Single Experiment ◽

Association Analyses ◽

Effective Manner ◽

Allele Dosage

AbstractNext-generation sequencing (NGS)-based genotyping methods can generate numerous genetic markers in a single experiment and have contributed to plant genetic mapping. However, the benefits of NGS-based methods are limited in autopolyploids as their genetic segregation mode is complex. Moreover, autopolyploids have large genomes and require abundant sequencing data to obtain sufficient genetic markers. There are several methods for genetic mapping in autopolyploids. These approaches may be impractical for plant genetic studies as they require large amounts of data and are not cost-effective. In the present study, we propose a simple strategy for genetic mapping of polyploids in a cost-effective manner. The allele dosage probabilities calculated from NGS read counts were used in association analyses to detect loci associated with specific phenotypes. This approach is superior to conventional methods of determining allele dosage, which usually result in the filtering of many genetic markers with low read depth. The validity of the strategy was demonstrated using real phenotype data from autohexaploid sweet potato populations to detect genetic loci for both qualitative and quantitative traits, the latter of which required the use of allele dosage probabilities for the detection of loci. We demonstrate that this proposed method is useful with reasonable NGS read counts.

Download Full-text