The Longest Day Complete Warcraft Achievement Guide. 1  Battle Pet achievement The Longest Day doesn't need to feel like the longest day! With some planning and a good route mapped out, it's possible to zoom through this entire achievement without devoting an entire day to the activity.
Histones are spools of proteins that surround the chromosome and control the switching on of genes. National Human Genome Research Institute. Changes made to the protein spools that surround chromosomes are passed down generations, proving that inherited traits are decided by more than just DNA, says a new study.
The presence of drugs or chemicals in an organism's environment can also influence gene expression in the organism. Cyclops fish are a dramatic example of the way in which an environmental chemical can affect development.imilarly, drugs, chemicals, temperature, and light are among the external environmental factors that can determine which genes are turned on and off, thereby influencing the way an organism develops and functions. Sex-influenced traits are those that are expressed differently in the two sexes.