Catherine W. Ernst

Identification of sequence tagged sites in the Asian and African elephant.

To date, gene identification in elephants has essentially related to evolutionary studies. Further identification of genes in elephants could provide additional information for evolutionary studies and for evaluating genetic diversity in existing elephant populations. The objective of this project was to identify sequence tagged sites (STSs) in the Asian and the African elephant for the following genes: melatonin receptor 1a (MTNR1A), retinoic acid receptor beta (RARB), and leptin receptor (LEPR). These genes are highly conserved among mammals, and all may play a role in reproduction. Heterologous primers for PCR were designed from sequences available in other species. Fragments of size 141 base pairs (bp) for RARB and 327 bp for LEPR were obtained by amplifying genomic Asian and African elephant DNA. The LEPR fragment included an intron of 164 bp. Also, a 417 bp fragment for MTNR1A was obtained in the Asian elephant only. All PCR products were sequenced and comparison computations were made at the nucleotide and amino acid levels to sequence available in the GenBank database. Nucleotide sequence for RARB was identical for both Asian and African elephants and differed by only 3 bp for LEPR. Deduced amino acid sequence was identical for both STSs in both species. Elephants were relatively similar in comparison to other mammals and less similar to chickens.

A strategy to rapidly identify restriction fragment length polymorphism (RFLP) in PCR products for gene mapping in animal families

▼Restriction fragment length polymorphisms (RFLPs) were first introduced as a tool for genetic analysis in the early 1970s and quickly became the major type of marker applied in the 1980s. Botstein et al. (Ref. 1) suggested the development of a human RFLP linkage map using markers detected by Southern blot hybridization analysis. However, the Southern RFLP suffers from drawbacks, such as the requirements for relatively large amounts of DNA, time and labor. Recently, PCR-based techniques such as random amplified polymorphic DNA (RAPD), simple sequence repeats (SSRs), and amplified fragment length polymorphism (AFLP) have been developed to identify highly polymorphic DNA markers. These techniques have shown great success in identifying informative molecular markers but have primarily been used for the initial development of anonymous markers. In targeting marker development at specific genes, PCR-RFLP, which primarily detects single-base polymorphisms in a piece of genomic DNA amplified by PCR, plays a major role in identifying polymorphism within gene sequences. A PCR-RFLP marker is the variation in DNA restrictionfragment pattern defined by applying a restriction enzyme or enzymes to the PCR product amplified from a set of