The great white shark is notable for its size, with mature female individuals growing up to 6.1 m (20 ft) in length and 1,950 kg (4,300 lb) in weight. However most are smaller, males measuring 3.35 to 3.96 m (11 ft 0 in to 13 ft 0 in) and females 4.57 to 4.88 m (15 ft 0 in to 16 ft 0 in) on average.
For most ALS genes, only one mutated copy is needed to cause disease. This is called a âdominantâ gene. For other genes, both copies must be mutated to cause disease. This is called a ârecessiveâ gene. During formation of eggs and sperm, gene pairs split up, so that an egg (or sperm) contains only one gene copy.
The study therefore describes a major cause of familial ALS in the Finland located on chromosome 9p21. Furthermore, the overlap with the risk haplotype (a combination of DNA sequences) recently also reported for frontotemporal dementia provides further evidence of a shared genetic cause for these two neurodegenerative diseases.