Understanding Dominant Traits

• To understand dominant traits, it is important to also understand recessive traits. A recessive gene can only be shown in human offspring when both parents have the recessive gene. The dominant gene, then, will be shown whenever at least one parent expresses the dominant gene. A dominant gene will always be expressed in a child whose parents both have the dominant gene.
  
  

Examples of Dominant Traits

• Becoming aware of some of the most common dominant traits can help you gain a more complete understanding of what a dominant trait is. For example, curly hair is a dominant trait over straight hair. Brown eyes are a dominant trait over every other eye color, including blue, green, hazel and grey. Normal hearing is a dominant gene over congenital deafness. Having extra finger and toe digits is dominant over having ten fingers and toes.
  
  

Commonness of Dominant Traits

• Many people mistakenly assume that dominant traits are more commonly expressed in the human population than recessive traits. However, some recessive genes appear much more often in the human population than their dominant counterparts. For example, although having extra finger and toe digits is the dominant gene over having just ten fingers and toes, the majority of the population has only ten fingers and toes. This just means that more people possess the recessive gene to pass along to their offspring.
  
  

How Dominant Traits are Passed

• When two parents reproduce their offspring takes genes from each parent. Dominant genes are expressed in children when both parent or one parent possesses the dominant gene. However, if neither parent possesses the dominant gene, then the child will demonstrate the recessive gene. For example, if neither parent has the gene for normal hearing, which is dominant over congenital deafness, the child will be deaf because he will take the recessive gene from his parents instead of the dominant gene. However, if one parent has the gene for normal hearing, the child will hear normally even if his other parent has the gene for congenital deafness, because it only takes one dominant gene to outdo a recessive gene.