Explanation:
base on the person opinion
Climate, Land form/shape and fossils(he was most interested in this)
Researchers selected candidate genes by identifying homozygous tracts shared by all three siblings along with the parental phenotype, this type of study is applied for the inheritance of recessive genes. Since the recessive genes can not be expressed in heterozygous genotype, the back tracking of carriers and homozygous recessive individual will help understand its inheritance pattern. The inheritance of dyt2 can be autosomal recessive. It is usually passed on to progeny of two carriers.
Because without it you would have no support to stand