Porcine ESTs detected by differential display representing possible candidates for the trait ‘eye muscle area’

In order to identify ESTs which represent possible candidates for carcass traits in pigs, the differential display approach was used. F 2 animals of a resource population and pure‐bred German Landrace (DL) pigs were selected for the trait ‘eye muscle area’ in order to build up groups of three high and three low performing individuals within each population. To increase the probability that differentially expressed DNA fragments were not found due to the genetic background but due to differences in a few genes affecting the trait of interest, siblings were included in the high and in the low performing groups. RNA was isolated from M. longissimus dorsi and four ‘intra‐litter constrasting pools’ were prepared: high performing F 2 , low performing F 2 , high performing DL and low performing DL. Differential display banding patterns were produced using (d)T 11 VA (V:A,C,G) and 20 arbitrary primers. Comparing the banding patterns of the four RNA pools revealed 27 nonshared bands. Here we report on the analysis of seven of these bands, including sequencing, search for homology and mapping using a somatic cell hybrid panel. Two clones showed high homology to known genes, two were homologous to an EST and a SINE sequence. Three clones did not show any homology. Differential expression was tested by semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) and could be confirmed for six clones.