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.
Genotype refers to the genetic makeup of a cell. For each individual trait (such as hair or eye color), a cell contains instructions on two alleles, which are alternative forms of the gene obtained from the mother and the father.