Figure 4.

Map positions of TASs of the Right End of the 81-MAC Common Region. Sequences of three O. trifallax alleles and three O. fallax 3.5 alleles across the multi-TAS region right of the Common Region are aligned. TAS positions, defined as the nucleotide 5' of the telomere repeats block, dGGGGTTTTGGGGTTTTGGGG, were inferred from mobilities of display bands (see Fig. 2), and are shaded in this figure. Three mapped O. fallax TASs are known from sequences of cloned chromosomes [27]; they are indicated by white letters with black backgrounds. The two start sites of transcription of the CR gene, mapped by Williams and Herrick [54], are indicated below the beginning of the alignment, in a region of nearly perfect conservation, excepting a bold-faced T in the O. fallax vA sequence. It is tightly associated with a dA TAS in this allele, which is indicated with a "/" below it. The stop codon of the Right Arm gene [25] is underlined. Asterisks above the alignment mark positions with a TAS unique to one allele; daggers mark positions where some, but not all alleles have a TAS. In 5 cases, the inferred position is followed directly by a dG. Because telomerase can complete GGGG runs, it is possible (discussed by [38]) that in each of these cases, the TAS was not at the inferred dT or dA, but instead could have been at the following dG; to indicate these ambiguous cases, the T or A and its 3' G are shown in lower case.