A human genome YAC library in a selectable high-copy-number vector

Area of Science:

• Genetics
• Molecular Biology
• Biotechnology

Background:

• Yeast artificial chromosomes (YACs) are crucial for constructing large-insert genomic libraries.
• Developing YAC vectors that allow for high copy numbers is essential for efficient screening and amplification.
• Previous methods for YAC library construction faced limitations in insert size and copy number.

Purpose of the Study:

• To create an experimental yeast artificial chromosome (YAC) library with a high-copy-number (hcn) vector for human DNA.
• To optimize YAC insert size and obtain larger clones by incorporating polyamines.
• To establish efficient screening methods for identifying specific loci within the YAC library.

Main Methods:

• Preparation of a yeast artificial chromosome (YAC) library using a selectable high-copy-number (hcn) YAC vector.
• Screening for unique loci via PCR of progressively smaller DNA pools and hybridization to high-density microcolony blots.
• Optimization of YAC insert size through the addition of polyamines during yeast transformation.

Main Results:

• The experimental YAC library contained one genome equivalent of human DNA with average insert sizes of 200 kb.
• Addition of polyamines resulted in YACs with average insert sizes of approximately 650 kb.
• YACs were identified for 17 out of 29 sequence-tagged sites (STS) using PCR-based screening.
• YACs in the 100-600 kb range could be amplified to significantly elevated copy numbers in supplemented media.

Conclusions:

• The developed hcn YAC vector facilitates the generation of large-insert human DNA libraries.
• Polyamines enhance the size of YAC inserts, improving genomic coverage.
• Efficient PCR-based screening and high-density hybridization methods are effective for locus identification.
• The hcn YACs are suitable for amplification, enabling applications in genetic research and diagnostics.