Without enough thyroid hormone, metabolism slows, making weight gain more likely. Even a thyroid functioning at the lower end of the normal range might cause weight gain. Treating hypothyroidism with medication may reverse some of the weight gain. If you have any concerns, seek medical advice.
1 Allele: a different version of a gene. 2  Dominant: a trait that is visible and can cover up other traits when there is more than one present. 3  Genotype: the genetic makeup of an organism, or the versions of a gene that an organism has. 4  Heterozygous: having two different versions of a gene.
A trait is a specific characteristic of an organism. Traits can be determined by genes or the environment, or more commonly by interactions between them.The genetic contribution to a trait is called the genotype.The outward expression of the genotype is called the phenotype.raits can be determined by genes or the environment, or more commonly by interactions between them. The genetic contribution to a trait is called the genotype. The outward expression of the genotype is called the phenotype.