Is Cystic Fibrosis homozygous or heterozygous?
Mendelian Genetics
| Genotype | Phenotype | |
|---|---|---|
| F F | Homozygous dominant | No cystic fibrosis (Normal) |
| F f | Heterozygous | Carrier (has no symptoms but carries the recessive allele) |
| f f | Homozygous recessive | Cystic fibrosis (has symptoms) |
Does cystic fibrosis have a heterozygous advantage?
Cystic fibrosis (CF) is the most common fatal genetic disorder of caucasians. While it has been hypothesized that there is a CF heterozygote advantage which allowed the gene to achieve such high prevalence, the nature of that advantage remains a mystery.
What type of mutation is Delta F508?
Cystic Fibrosis The most common mutation in the CFTR gene is ΔF508, a frameshift mutation caused by a three base-pair deletion at codon 508 in exon 10 of CFTR, resulting in the absence of a phenylalanine residue.
What is the genotype of a person with CF?
The genotype of the carrier is Ff (one dominant non-disease gene, F, and one recessive, CF gene, f).
Is DD heterozygous or homozygous?
| Individual | Genotype | |
|---|---|---|
| Sam (father) | DD | homozygous dominant |
| Sally (mother) | dd | homozygous recessive |
| Susan (child) | Dd | heterozygous |
What does Delta F508 cause?
The most common mutation in the gene associated with cystic fibrosis (CF) causes deletion of phenylalanine at residue 508 (delta F508) of the gene product called CFTR. This mutation results in the synthesis of a variant CFTR protein that is defective in its ability to traffic to the plasma membrane.
Why is being heterozygous beneficial?
This is termed heterozygote advantage. It is important because even a slight heterozygote advantage may act to increase the frequency of the mutant allele in the population—even if the mutant allele causes major reduction in fitness in homozygotes in that population.