Your genetics aren't the only determinants of your phenotype (what traits you display). Identical twins have identical (the same) genes. What are two phenotype differences identical twins could have that are not the results of their genes? what would cause that?
Two phenotype differences that identical twins could have, which are not solely determined by their genes, could be:
1. Developmental factors: Even though identical twins share the same genes, they can still have differences in phenotype due to various developmental factors. For example, differences in prenatal environment or in the conditions and experiences during their growth and development can influence how genes are expressed. These factors can include variations in nutrition, exposure to different levels of hormones or chemicals, or variations in the care and attention received from parents or caregivers.
2. Epigenetic modifications: Epigenetic modifications are changes in gene expression that occur without altering the DNA sequence. These modifications can be influenced by various environmental factors and can result in different phenotypes even among genetically identical individuals. For instance, differences in DNA methylation, histone modifications, or non-coding RNA interactions can lead to variations in gene activity and expression. Environmental factors such as stress, diet, or exposure to toxins can affect these epigenetic modifications and result in phenotypic differences between identical twins.
Overall, while genetics plays a significant role in determining phenotype, environmental and epigenetic influences can lead to variations among genetically identical individuals.