After the Dambusters raid in 1943 an entirely new system was developed that was required to knock down any low-flying aircraft with a single hit. The first attempt to produce such a system used a 50 mm gun, but this proved inaccurate and a new 55 mm gun replaced it. The system used a centralised control system including both search and targeting radar, which calculated the aim point for the guns after considering windage and ballistics, and then sent electrical commands to the guns, which used hydraulics to point themselves at high speeds. Operators simply fed the guns and selected the targets. This system, modern even by today's standards, was in late development when the war ended.
What did the new system designed after the Dambusters raid supposed to do?
knock down any low-flying aircraft with a single hit

The analysis of HLA antigens has also helped clarify the possible background of the Somali people, as the distribution of haplotype frequencies vary among population groups. According to Mohamoud et al. (2006):
In what year did Mahamoud publish his research?
2006

Housekeeping genes are critical for carrying out basic cell functions and so are expressed at a relatively constant level (constitutively). Since their expression is constant, housekeeping genes are used as experimental controls when analysing gene expression. Not all essential genes are housekeeping genes since some essential genes are developmentally regulated or expressed at certain times during the organism's life cycle.
When are some essential genes expressed?
at certain times during the organism's life cycle