Genomic organization, sequence and polymorphism of the human chromosome 4-specific alpha-satellite DNA.
Two alpha-satellite fragments specific for human chromosome 4 have been cloned and characterized. Under stringent annealing conditions, they hybridized in situ only to the pericentromeric region of chromosome 4, but under non-stringent conditions they hybridized to all chromosomes containing the sequences of alpha-satellite suprachromosomal family 2 (viz., chromosomes 2, 4, 8, 9, 13, 14, 15, 18, 20, 21 and 22). Southern blot analysis reveals the 3.2-kb higher-order repeated unit which exists in two forms: as a single MspI fragment or a combination of the 2.6-kb and 0.6-kb MspI fragments. The two chromosome-4-specific cloned sequences appear to be different parts of this repeated unit. Taken together they constitute about 60% of its length. The primary structure of the higher-order repeated unit is characterized by a dimeric periodicity of the D1-D2 type which is usual to suprachromosomal family 2. At least in one site this regularity is disrupted by monomer deletion leading to the D2-D2 monomeric order. The most likely mechanism of this monomer excision is homologous unequal crossing-over. These sequences may serve as both cytogenetic and restriction-fragment length polymorphism (RFLP) markers for the pericentromeric region of chromosome 4.
Mashkova
T D
TD
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow.
Akopian
T A
TA
Romanova
L Y
LY
Mitkevich
S P
SP
Yurov
Y B
YB
Kisselev
L L
LL
Alexandrov
I A
IA
D001483:Base Sequence; D015139:Blotting, Southern; D002894:Chromosomes, Human, Pair 4; D004276:DNA, Satellite / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid
D004276:DNA, Satellite