Multiple interchange stocks for linkage detection

Multiple interchange stocks for linkage detection Creative Commons License This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License. This technical note is available in Fungal Genetics Reports: http://newprairiepress.org/fgr/vol6/iss1/18 Perkins,.D. D. Multiple interchange stocks for linkage detection. The following strains, each containing three reciprocal translocations, have been synthesized for the purpose of osrigning new mutants to linkage groups with o minimum of labor: T(1;II )&l; T(IV;V)2355, g; T(III;VI)I,&A (Designated olcoyAJ (Fungal Genetics Stock Center # 997) T (I;II)&l; T (IV;V )2355, JZ&; T(III;VI)l, &g (Designated alcoy 0) (Fungal Genetics Stock Center # 998) In each tromlocotion o readily scored “visible” marker either is present ot the interchange point (&J) or hm been inserted clcee to it (bond &), so that linkage to either of the two groups involved in the trontlocation con be detected by linkage to the visible marker. albino-l u, 4637T) marks IR and IIR (near peach ); colonial-temperature remitive (d, Cl02 ) marks IVR and VR (near histidine-I ); yellow (yj~, Y30539y) marks VI1 and IIIR (near velvet). (‘: Ia. .̂ ,,:, $2 Rocedure: Use olcoy os protoperithecial parent on 2% ogor slants of minimal synthetic crcering medium :. in 15x Incubate 6 or 7 days at 25’ before fertilizing with the mutant to be mopped. Isolate 100 black spores to minimal ogar slants in 75 mm tubes. (If the unmapped mutant is on ouxotroph, isolate 200 to minimal and score only among the prototrophs.) Isolate not earlier than one week (25’) after spores ore shot. Heatshock and incubate 2 to 3 days at 34O. Sort out & progeny, which hove grown up at 34O. Move remaining tiber (not grown up at 34’) to 25O, to allow growth of a. Score albino, yellozr, and the unmapped mutant at 6 days growth. &is storable only omongd+ progeny. The following format is useful for tabulating numbers (P = parental, R = recombinant ): unmapped mutant coti)lliI/p1 (Tests for linkage in IV or V.) I I I ol:F1 (TestsforlinkogeinIorII.) (Tests for linkage in III or VI.) I I I I f linkage to one of the three markers is opporent, follow up either with crosses to markers in the individual group concerned, or with other marked multiple-tronslocation testers whose interchanges straddle the groups interchanged in olcoy. If no linkage is apparent to ony of the olcoy markers, the unmapped mutant is presumably in VII (or possibly at the extreme left of I, III, IV or V). In crosses between olcoy and stroim with normal chromosome sequence, about one-eigth of shot oscospores ore black. Presence of the three tronslocotions has been confirmed both genetically (by the author) and cytologically at prophase 1 (by E. G. Barry). Of 44 previously unmapped mutants tested with olcoy, linkage to one or another of the alcoy markers has been shown by 34. Department of Biological Sciences, Stanford University, Stanford, California.