(1) The yellow and white of the tiger is a relative character. The offspring of white tiger and yellow tiger are yellow tigers, which shows that white is recessive and yellow is dominant in coat color, and the genomes controlling the coat color of the two tigers are homozygous. If the dominant gene is represented by a and the recessive gene is represented by a, then the genetic composition of white tiger and tiger cub is aa and AA respectively.

(2) According to the gene map, the probability of the offspring of yellow tiger mating with white tiger is 50%.

(3) The measures to protect biodiversity are: first, in-situ protection, mostly the construction of nature reserves, such as Sichuan Wolong Giant Panda Nature Reserve; Second, ex-situ conservation, mostly transferred to zoos or botanical gardens, such as bringing Metasequoia seeds to Nanjing Sun Yat-sen Mausoleum Botanical Garden for planting; The third is to carry out scientific research on biodiversity protection and formulate laws and policies on biodiversity protection; Fourth, carry out publicity and education on biodiversity protection. Putting the white tiger in the zoo for breeding belongs to ex situ conservation.

Therefore, the answer is: (1) yellow hair; aa； alcoholic anonymous

(2)50%( 1/2)

(3) Relocation