1. CHARACTERIZATION OF A MATERNAL EFFECT ALLELE INFLUENCING THE DEVELOPMENT OF LEFT-RIGHT AXIS. This is my main research interest and it was the main part of my PhD program. In a recent study Facchin and collaborators (2009) showed that the progeny of zebrafish lines artificially selected for the right eye preference in a behavioral test, had a significant increase in the frequency of reversed left-right asymmetry of the epithalamus. Based on a preliminary mendelian analysis of this trait, we performed selective crosses on animals identified as mutant carriers confirming the hypothesis of a recessive maternal effect mutation.
We identified three different classes in the group of analyzed females according to the percentage of reversed brain asymmetries in their offspring. Females generating a frequency of 0-5% (class I), between 5 and 12.5% (class II) and females generating more than 12.5% (class III) of progeny with reversed asymmetries. Animals from the last group were considered as homozygous recessive females (HRF).
We investigated in this strain the expression of members of signaling pathways responsible for the establishment of visceral and diencephalic left-right asymmetries and measured the size of Kupffer’s vescicle (KV) finding that HRF offspring had smaller KV and, sometimes, no vesicle at all. We could observe a negative correlation between the frequency of reversed parapineal and the size of KV.
Our hypothesis suggests that smaller size of KV can reduce the amount of morphogens accumulated by the leftward flow, thus leading to a randomization of the expression of genes of the Nodal pathway. This project is ultimately focused on the identification of the putative mutation through next generation sequencing techniques in collaboration with professor Giorgio Valle genomic group.

2. ASSOCIATION BETWEEN EPITHALAMIC ASYMMETRIES AND BEHAVIORAL LATERALIZATION (in collaboration with Angelo Bisazza and Marco Dadda). Nowadays we have very little knowledge about the possible linkage between neuroanatomical asymmetries and lateralized behavior. Zebrafish represents a powerful model to investigate this topic. We aimed at comparing lines of fish selected for opposite parapineal position in a series of test that estimate population- level fitness, moreover we will study individual consistency and ontogeny of lateralization.

3. CHARACTERIZATION OF A TRANSGENIC INSERTION SITE THAT LEADS TO TUMORIGENESIS. In our fish facility we regularly observed that transgenic nkx2.2a::GFP (-8,5 kb) fish (Pauls et al., 2007) develop massive tumors in different organs. In these years we shared this transgenic line with other laboratories and they observed the same situation. Moreover this transgenic line is unavailable as homozygous. We then decided to characterize the transgenic insertion site and possibly give an explanation to tumor development.