[lemma=by] [word=keeping | lemma=a] [tag=□] □
[lemma=by] [word=keeping | lemma=a] [tag=JJ] □
In terms of gene regulation , a high correlation ( or anti-correlation ) between A and B can be caused by ( 1 ) gene A regulating gene B , ( 2 ) gene B regulating gene A , ( 3 ) gene A and B being co-regulated by a third gene C , or ( 4 ) accident . Now let 's assume that red-green color blindness is controlled by a dominant gene on the sex linked X chromosome . A person heterogygous for a genetic disease caused by a dominant gene will be affected with the disease . This makes it easier for researchers to study recessive mutations , since the defects in a gene inherited from one parent will show up more clearly if they are not compensated by a normal gene from the other parent . F1 individuals to the SPF White Leghorns did not differ significantly from the expected ratio of 1 LSN :1 normal based on the assumption that the LSN trait is controlled by a dominant gene ( Table 1 ) . Huntington 's disease - a degenerative hereditary disorder caused by a faulty gene for a protein called huntington . Huntington 's disease ( HD ) is a hereditary disorder caused by a faulty gene for a protein called huntingtin . Researchers in France and the United Kingdom , knowing the disease was caused by a faulty gene on the X chromosome , treated 14 children by replacing the faulty gene ex vivo . They are also searching for the obese receptor , encoded by a second gene called db , short for diabetes , which Friedman believes is a key to future efforts to target " smarter " drugs to combat obesity . In less than 5 percent of HUS cases , the disorder is inherited by a dominant gene ( a gene passed from parent to child with a 50/50 risk ) or recessive gene ( each parent carries one copy of the gene and the child inherits both copies ; the chance is 25 percent with each pregnancy ) . The mid-digital hair trait is determined by a dominant gene ( M ) for each finger causing hair to grow on the top of that finger . Moreover , research has demonstrated that about 50 percent of Alzheimer 's disease is caused by a faulty gene ( s ) , presumably affecting the expression of specific brain proteins such as beta-amyloid . When it is replaced by a normal gene , the mice no longer develop signs of the disease . The French trial was attempting to treat x-SCID , a rare inherited disorder caused by a faulty gene , which affects boys .