Arl13a, a member of the Arf-like (Arl) family of small GTP-binding proteins, is a close paralog to Arl13b. These proteins are involved in regulating various cellular functions and play crucial roles in cilia structure and signaling. Genetic models, like zebrafish, can be valuable for studying Arl13a [1].

In zebrafish, Arl13a and Arl13b are both widely expressed during early cell division and gastrulation, localizing to microtubules in ciliated and dividing cells. However, between 2-5 days post-fertilization, Arl13b is expressed in neural tissues while Arl13a expression is downregulated by 2 dpf and restricted to craniofacial structures, indicating different evolved roles and suggesting Arl13a does not function in the zebrafish retina [1]. In cheetahs, mutations in Arl13a, along with three other genes (DEFB116, CFAP119, and NT5DC4), are linked to male fertility and immune deficiencies, likely due to pseudogenization events [2,3].

In conclusion, Arl13a is involved in cilia-related functions and may have tissue-specific expression patterns during development. The findings from zebrafish and cheetah studies suggest its role in non-retinal development in zebrafish and its potential link to male fertility and immune deficiencies in cheetahs, highlighting its importance in understanding both normal development and certain disease-related conditions.