Autosomal Dominant Traits

Autosomal Dominant Traits

1. Marfan Syndrome

   • Arm span always exceeds height
   • Arachnodactyly
   • Tall, thin phenotype
   • Loose-jointedness
   • Abnormal curvature of the spine
   • Enlarged aorta (aneurysm)
   • The gene associated with Marfan Syndrome encodes the protein fibrillin
     • Fibrillin creates a sheath around the elastin fibbers found in connective tissue
     • The gene that encodes fibrillin is found on chromosome 15
   • If a person has one copy of the defective allele, the Marfan Syndrome phenotype will be seen
   • Autosomal dominant disorder

2. Tennessee Fainting Goats

   • These goats become stiff and fall over when startled
   • Often called wooden-leg goats or stiff-leg goats
   • These goats have an autosomal dominant condition called Myotonia
     • The Myotonia gene encodes a chloride channel protein found in muscle cells

3. Cloverleaf Tongue

   • Rare dominant trait
   • An individual with this trait is most likely heterozygous