title: Characterization of four human YAC libraries for clone size, chimerism and X chromosome sequence representation.
abstract: Four collections of human X-specific YACs, derived from human cells containing supernumerary X chromosomes or from somatic cell hybrids containing only X human DNA were characterized. In each collection, 80-85% of YAC strains contained a single X YAC. Five thousand YACs from the various libraries were sized, and cocloning was assessed in subsets by the fraction of YAC insert-ends with non-X sequences. Cocloning was substantial, ranging up to 50% for different collections; and in agreement with previous indications, in all libraries the larger the YACs, the higher the level of cocloning. In libraries made from human-hamster hybrid cells, expected numbers of clones were recovered by STS-based screening; but unexpectedly, the two collections from cells with 4 or 5 X chromosomes yielded numbers of YACs corresponding to an apparent content of only about two X equivalents. Thus it is possible that the DNA of inactive X chromosomes is poorly cloned into YACs, speculatively perhaps because of its specialized chromatin structure.
authors.affiliation: Center for Genetics in Medicine, Washington University School of Medicine, St Louis, MO 63110.
authors.forename: R
authors.initials: R
authors.lastname: Nagaraja
authors.forename: J
authors.initials: J
authors.lastname: Kere
authors.forename: S
authors.initials: S
authors.lastname: MacMillan
authors.forename: M J
authors.initials: MJ
authors.lastname: Masisi
authors.forename: D
authors.initials: D
authors.lastname: Johnson
authors.forename: B J
authors.initials: BJ
authors.lastname: Molini
authors.forename: G R
authors.initials: GR
authors.lastname: Halley
authors.forename: K
authors.initials: K
authors.lastname: Wein
authors.forename: M
authors.initials: M
authors.lastname: Trusgnich
authors.forename: B
authors.initials: B
authors.lastname: Eble
mesh_terms: D000818:Animals; D001483:Base Sequence; D002678:Chimera; D018244:Chromosomes, Artificial, Yeast; D003001:Cloning, Molecular; D006224:Cricetinae; D004247:DNA / Q000737:chemistry; D015723:Gene Library; D006801:Humans; D006822:Hybrid Cells; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016133:Polymerase Chain Reaction; D014960:X Chromosome
chemical_list: D004247:DNA