Higher-order repeat structure in alpha satellite DNA is an attribute of hominoids rather than hominids
Terada S, Hirai Y, Hirai H and Koga A*
satellite DNA (AS), a major DNA component of primate centromeres, is
composed of a tandem array of repeat units of approximately 170?bp. The AS
of hominids (family Hominidae; humans and great apes) includes sequences
organized into higher-order repeat (HOR) structures, with a periodic
appearance of multiple copies of the basic repeat units. Here, we
identified an HOR in AS of the siamang, a small ape phylogenetically
distinct from hominids but included in hominoids (superfamily Hominoidea).
We sequenced long stretches of genomic DNA, and found a repetition of
blocks consisting of six and four basic repeat units. Thus, AS
organization into HOR is an attribute of hominoids, rather than, as
currently postulated, hominids. In addition to centromeres, siamangs carry
AS in terminal heterochromatin blocks, and it cannot be determined at
present whether these HOR-containing AS sequences originate from the
centromere or from the terminal heterochromatin. Even if the latter is the
case, these sequences might affect the composition of centromeric AS by
being transferred to the centromere.
Journal of Human Genetics (2013): Advance online publication. DOI: 10.1038/jhg.2013.87
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