The complete coding sequence for mouse tropoelastin was obtained from overlapping reverse transcriptase polymerase chain reaction (PCR) amplimers. These cDNA fragments were derived from mouse tropoelastin mRNA using PCR oligomers complementary to conserved domains within rat tropoelastin mRNA. A comparison of coding domains of mouse and rat tropoelastin mRNA revealed a greater than 93% homology at the nucleotide level and over 96% similarity in the predicted amino acid sequence. PCR primers complementary to regions of the mouse tropoelastin mRNA were used to define a novel intron length polymorphism (ILP) within intron 8 of the mouse tropoelastin gene (Eln). This ILP proved to be informative in an interspecific backcross in which genomic DNA samples from 75 backcross mice were used to map the tropoelastin gene to a position in the distal half of mouse chromosome 5. The linkage and genetic distances between Eln and the closest molecular markers used in this study are centromere-D5Mit95, D5Mit96-6.7 cM-Gus, Eln-4.0 cM-Zp3-telomere.