Theoretical and Applied Genetics

, Volume 77, Issue 1, pp 95–101 | Cite as

Restriction fragment length polymorphism maps and the concept of graphical genotypes

  • N. D. Young
  • S. D. Tanksley


With the advent of high density restriction fragment length polymorphism (RFLP) maps, it has become possible to determine the genotype of an individual at many genetic loci simultaneously. Often, such RFLP data are expressed as long strings of numbers or letters indicating the genotype for each locus analyzed. In this form, RFLP data can be difficult to interpret or utilize without complex statistical analysis. By contrast, numerical genotype data can also be expressed in a more useful, graphical form, known as a “graphical genotype”, which is described in detail in this paper. Ideally, a graphical genotype portrays the parental origin and allelic composition throughout the entire genome, yet is simple to comprehend and utilize. In order to demonstrate the usefulness of this concept, graphical genotypes for individuals from backcross and F2 populations in tomato are described. The concept can also be utilized in more complex mating schemes involving two or more parents. A model that predicts the accuracy of graphical genotypes is presented for hypothetical RFLP maps of varying marker spacing. This model indicates that graphical genotypes can be more than 99% correct in describing a genome of total size, 1000 cM, with RFLP markers located every 10 cM. In order to facilitate the application of graphical genotypes to genetics and breeding, we have developed computer software that generates and manipulates graphical genotypes. The concept of graphical genotypes should be useful in whole genome selection for polygenic traits in plant and animal breeding programs and in the diagnosis of heterogenously based genetic diseases in humans.

Key words

RFLPs Haplotypes Selection 


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  1. Bender W, Akam M, Karch F, Beachy P, Peifer M, Spierer P, Lewis EB, Hogness DS (1983) Molecular genetics of the bithorax complex in Drosophila melanogaster. Science 221:23–29Google Scholar
  2. Bernatzky R, Tanksley S (1986) Toward a saturated linkage map in tomato based on isozyme and random cDNA sequences. Genetics 112:887–898Google Scholar
  3. Burr B, Burr FA, Thompson KH, Albertson MC, Stuber CW (1988) Gene mapping with recombinant inbreds in maize. Genetics 118:519–526Google Scholar
  4. Donis-Keller H, Green P, Helms C, Cartinhour S, Weiffenbach B, Stephens K, Keith TP, Bowden DW, Smith DR, Lander ES, Botstein D, Akots G, Rediker KS, Gravius T, Brown VA, Rising MB, Parkers C, Powers JA, Watt DE, Kauffman ER, Bricker A, Phipps P, Muller-Kahle H, Fulton TR, Ng S, Schumm JW, Braman JC, Knowlton RG, Barker DF, Crooks SM, Lincoln SE, Daly MJ, Abrahamson J (1987) A genetic linkage map of the human genome. Cell 51:319–337Google Scholar
  5. Lander ES, Botstein D (1986) Strategies for studying heterogeneous genetic traits in humans by using a linkage map of restriction fragment length polymorphisms. Proc Natl Acad Sci USA 83:7353–7357Google Scholar
  6. Osborn TC, Alexander DC, Fobes JF (1987) Identification of restriction fragment length polymorphisms linked to genes controlling soluble solids content in tomato fruit. Theor Appl Genet 73:350–356Google Scholar
  7. Paterson AH, Lander ES, Hewitt JD, Peterson S, Lincoln SE, Tanksley SD (1988) Resolution of quantitative traits into Mendelian factors by using a complete RFLP linkage map. Nature (in press)Google Scholar
  8. Rick C (1974) High soluble-solids content in large-fruited tomato lines derived from a wild green-fruited species. Hilgardia 42:493–510Google Scholar
  9. Sharma AK, Sharma A (1980) Chromosome techniques: theory and practice, 3rd edn. Butterworth, LondonGoogle Scholar
  10. Smith CL, Econome JG, Schutt A, Klco S, Cantor CR (1987) A physical map of the Escherichia coli K12 genome. Science 236:1448–1453Google Scholar
  11. Tanksley SD, Hewitt J (1988) Use of molecular markers in breeding for soluble solids content in tomato — a re-examination. Theor Appl Genet 75:811–823Google Scholar
  12. Tanksley SD, Miller JC, Paterson A, Bernatzky R (1988) Molecular mapping of plant chromosomes. In: Gustafson JP, Appels R (eds) Chromosome structure and function. Plenum Press, New York, pp 157–173Google Scholar
  13. Tease C (1978) Cytological detection of crossing-over in BudR substituted meiotic chromosomes using the fluorescent plus Giemsa technique. Nature 272:823–824Google Scholar
  14. Zamir D, Selilabe-Davis T, Rudich J, Juvick JA (1984) Frequency distribution and linkage relationships of 2-tridecanone in interspecific segregating generations of tomato. Euphytica 33:481–488Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • N. D. Young
    • 1
  • S. D. Tanksley
    • 1
  1. 1.Department of Plant Breeding and BiometryCornell UniversityIthacaUSA

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