Chicken HOXC8 and HOXC10 genes may play a role in the altered skull morphology associated with the Crest phenotype.

One of the most intriguing traits found in domestic chickens is the Crest phenotype. This trait, characterized by a tuft of elongated feathers sprouted from the head, is found in breeds such as Polish chickens and Silkie chickens. Moreover, some crested chicken breeds also exhibit a protuberance in their anterodorsal skull region. Previous studies have strived to identify the causative factors of this trait. This study aimed to elucidate the role of chicken HOXC8 and HOXC10 in the formation of the Crest phenotype. We explored the effect of ectopic expression of HOXC8 or HOXC10 on the chicken craniofacial morphology using the RCAS retrovirus transformation system. Microcomputed tomography scanning was conducted to measure the 3D structure of the cranial bone of transgenic embryos for geometric morphometric analysis. We found that the ectopic expression of HOXC8 or HOXC10 in chicken heads caused mild morphological changes in the skull compared with the GFP-transgenic control group. Geometric morphometric analysis showed that HOXC8 and HOXC10 transgenic groups expressed a mild upward shape change in the frontal region of the skull compared with the control group, which is similar to what is seen in the crested chicken breeds. In conclusion, this study supports findings in previous studies in which HOX genes play a role in the formation of the altered skull morphology related to the Crest phenotype. It also supports that mutations in HOX genes may contribute to intra- and inter-specific variation in morphological traits in vertebrates.

Fabrication of a polymeric vertical microlens with the dip method.

We have investigated a process based on the dip method to fabricate a polymeric vertical microlens (PVM). After the primary dip step, the PVM is formed by hanging the liquid SU-8 on a wall in virtue of the strong adhesive force and liquid cohesion. The microlens is then baked and exposed in ultraviolet light to further cross-link the negative photoresist SU-8 to enhance thermal stability and reliability. According to the experimental results, the radius of curvature of the fabricated vertical microlens varies from 120.8 to 34.2 microm, which relates to the dip depth or the thickness of the dipped pool. To characterize the PVM, an edge-emitting laser diode (lambda=1.31 microm) is then bonded onto the optical bench and a detector is utilized to observe the beam divergence with and without the lens insertion. Compared with an angle of 40.8 degrees without the microlens, the beam passing through a suitable PVM shows a vertical far-field angle of 3.32 degrees. Furthermore, the lens efficiency, approximately 83.4%, is also specified by the measurements.