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.
Genes determine traits, or characteristics, such as eye, skin, or hair color, of all sexually-reproducing species. Each gene consists of two alleles: one comes from the mother and one from the father. Some alleles are dominant, meaning they ultimately determine the expression of a trait.Other alleles are recessive and are much less likely to be expressed.When a dominant allele is paired with a recessive allele, the dominant allele determines the characteristic. When these traits or characteristics are visibly expressed, they are known as phenotypes.The genetic code behind a trait is known as the genotype.hen a dominant allele is paired with a recessive allele, the dominant allele determines the characteristic. When these traits or characteristics are visibly expressed, they are known as phenotypes.