Assignment of the human folate transporter gene to chromosome 21q22.3 by somatic cell hybrid analysis and in situ hybridization.

We have used the human folate transporter cDNA and a human genomic clone hybridizing to the cDNA to perform chromosomal mapping of the folate transporter gene. Human-rodent somatic cell hybrid analysis using the cDNA as the probe revealed perfect segregation with human chromosome 21. In situ hybridization of the cDNA probe to human metaphase chromosome spreads mapped the folate transporter gene to the distal long arm of chromosome 21, band q22.3. This chromosomal location was confirmed by fluorescence in situ hybridization using the genomic clone.