REPETITIVE SEQUENCE FAMILIES IN ALCES-ALCES AMERICANA

High-resolution derivative melting was used to obtain detailed distrib utions of local (G + C) contents in a number of ruminant DNAs. Profile s over low (G + C) regions [20-36% (G + C)] are congruent for all rumi nants. This region represents 45-50% of the nuclear DNA content and pr imarily contains intergenic and intron sequences. The high (G + C) reg ion, where most coding sequences are found [38-68% (G + C)], is marked by satellite bands denoting the presence of transcriptionally inert, tandemly repetitive sequence families. These bands can be analyzed for the abundance, base composition, and sequence divergence of satellite families with relatively high precision. Band patterns are unique to each species; even closely related species can be readily distinguishe d by their base distribution profiles. Variations in nuclear DNA conte nts in ruminants, determined by flow cytometry, are primarily due to v ariations in abundances of these repetitive sequence families. Thus, A . alces (moose) is found to have 8.85 +/- 0.2 pg DNA/cell, 25% more th an the average in ruminants, while the base distribution curve indicat es the presence of an unusually abundant satellite of 52.6% (G + C). T he size (1 kb) and sequence of this satellite corresponds to satellite -I of other cervids, and in consequence it is designated Alces-I. The sequence of a cloned repeat of Alces-I has a length of 968 bp, a (G C) content of 52.6%, and contributes 35%, or almost 3 million copies t o the nuclear DNA, exceeding by similar to 300% the average array size of this repeat family in related cervids. In situ hybridization indic ates the repeat is distributed throughout centromeric regions of all 6 2 acrocentric autosomes. Alces-I has much greater-than-expected number s of GG, GA, and AG and far fewer numbers of TA and CG duplets, charac teristics of all tandem repeats. The sequence is judged to be ortholog ous with satellite-I sequences from Rangifer tarandus (caribou), Capre olus capreolus (roe deer), Muntiacus muntjac (Chinese muntjac) and Mun tiacus reevesi (Indian muntjac), as well as Antilocapra americana (pro nghorn), and the bovids Bos taurus and Ovis aries. A tentative tree fo r the five cervids is in excellent agreement with one proposed on the basis of morphological characteristics. Differences from a consensus s equence indicate transversions exceed transitions by almost twofold, s uggesting that substitutions occur randomly, or nearly so.