Hieronymus Cock Company

Sex Determination: Two Copies for One Cock

The molecular mechanism of sex determination in birds has long remained mysterious. Genetically male chicken embryos, which have two Z sex chromosomes, develop female gonads when the Z chromosome-linked gene DMRT1 is knocked out. This suggests that sex is determined by Z chromosome dosage.

Genital Evolution: Cock-a-Doodle-Don’t

Losing the penis in species with internal fertilization may seem paradoxical, but birds have managed to do it multiple times. A new study addresses one developmental mechanism responsible for penis reduction in birds, and opens the door to further examination of this little understood evolutionary phenomenon.

Commentary on de Cock Buning: a United kingdom perspective.

de Cock Buning (1998) highlighted the existence of alternative and more favorable options available to xenotransplantation. Clearly, there is a need to emphasize a review of existing organ procurement programs worldwide. A tree interest in the welfare of animals encourages increased liaison between transplant communities throughout the world to discuss the experiences of various procurement pro...

The glutamic acid and creatine content of cock seminal plasma.

reacting haemoglobin (Hb*) is formed. If pchloromercuribenzoate is added almost all the reduced haemoglobin formed is Hb*. At alkaline pH the chief product of photolysis is Hb* even in the absence of p-chloromercuribenzoate. 3. At alkaline pH Hb* reverts spontaneously to ordinary haemoglobin with a velocity constant of about 200 sec.-' at 10. 4. The second-order velocity constant for the combin...

Commentary on de Cock Buning: animal welfare problems in xenotransplantation.