A CFTR gene. The Cystic Fibrosis allele

A gene is a string of DNA molecules
that contain a message for a specific protein. The message is encoded in a
specific region in the form of specific nucleotide sequences. This will be
copied in the form of a messenger RNA sequence which will then be used to form
a protein. A mutation in the region of the gene will change the message,
thus changing the protein structure and its function. This is how diseases are
created. All living things depend on genes. Genes hold the information to build
and maintain their cells and pass genetic traits to offspring. In patients with
Cystic Fibrosis, the mucus layer on the surface of the epithelial cells is
sticky because it contains less water. This is due to abnormal salt and water
transport across the cell surface membranes, caused by a faulty transport
protein channel in the membrane. This is the CFTR protein. The basic cause for
a faulty gene of any sort, is a mistake in DNA replication. The faulty protein
can be caused by numerous mutations where the amino acid is completely missing,
or other mutations may have the wrong amino acid in a particular place. During
DNA replication, various stages occur. One of these is translation, the process
of putting together amino acids to make proteins. A mistake in translation can
produce mRNA with one or more incorrect codes. This results in a faulty
protein. Cystic Fibrosis is an autosomal recessive disorder which happens when
you have two recessive alleles of a CFTR gene. The Cystic Fibrosis allele is
recessive rather than dominant. If a man and a woman have a baby and the man
has Cystic Fibrosis and passes on his allele, the child will not have Cystic
Fibrosis, he will only be a carrier of the gene. The mother and father would
both have had Cystic Fibrosis to pass on the allele. It is recessive, meaning
you have to have two copies of the allele, one from each parent. If Cystic
Fibrosis was dominant, the child would need just one Cystic Fibrosis allele in
order to have it.