Possible Clues:

• Genetic change
• That'd start to turn your stomach for a change
• Pooch eating a particle, which makes a change
• Chromosomal alteration
• Chromosomal change
• Greek character has position that's missing opening variation
• This could make the mutton A1 for a change
• Genetic shift and amount it altered
• This might turn your stomach for a change if you're not A1
• Variant form (of gene)