Figure 3.

Meiotic crosses of lug1Δ strains with [URE3] and ure2Δ strains. Left: lug1Δ strain YHE1633 crossed with [URE3] strain YHE1627 showing three typical tetrads. Medium 1 = 1/2 YPD (limiting adenine), medium 2 = yeast nitrogen base medium with galactose (Gal) and raffinose (Raf) as carbon sources (2% each), medium 3 = YPG, and medium 4 = YPG growth of diploids (Dipl.) formed with the meiotic segregant and a ρ^o strain of opposite mating type as a check on loss of mitochondrial DNA. Spore clones with the lug1Δ allele are underlined in yellow. The occasional spore clone that spontaneously lost [URE3] appears red on 1/2 YPD. In general, lug1Δ [URE3] segregants could not grow on YPG and grew poorly on the minimal Gal/Raf medium. Right: A typical tetrad from a cross of lug1Δ strain YHE1630 and ure2Δ strain YHE1636. The media are as for the left cross. Segregants with lug1Δ are underlined in yellow and ure2Δ segregants appear white on 1/2 YPD (medium 1). In general, lug1Δ ure2Δ segregants did not grow on YPG and poorly on minimal Gal/Raf medium, and had not lost their mitochondrial DNA.