Human genetics is the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling.
Genes can be the common factor of the qualities of most human-inherited traits. Study of human genetics can be useful as it can answer questions about human nature, understand the diseases and development of effective disease treatment, and understand genetics of human life. This article describes only basic features of human genetics; for the genetics of disorders please see: medical genetics.
Galactosemia is an autosomal recessive hereditary disorder caused by a deficiency of the enzyme galactose-1- phosphate uridyl transferase (GALT) that is needed for the breakdown of the milk sugar, galactose.
Representation of the double helix structure of human DNA
The chart very nicely lays out the amino acid each codon corresponds to. You're looking for "trp" in the chart, which only appears once, beside the UGG codon. Therefore, only one codon codes for tryptophan.