Most children with cystic fibrosis have frequent lung infections and digestive difficulties. Some
people have mild cases, with onset of minor respiratory problems in adulthood. Some men with
cystic fibrosis only exhibit the symptom of infertility. Which exception to Mendelian laws of
inheritance best explains these symptoms?
1.) incomplete dominance
2.) pleiotropy
3.) epistasis
4.) codominance
5.) overdominance
Solution
2. Pleiotropy.
Some genes influence not only the triats generally associated with them but also many other
triats. The multiple effect of a gene is called pleiotropy and gene having multiple phenotypic
effects is called pleiotropic gene.
Pleiotropic genes may not have equal influecne on all triats they control and these genes may
cause a very evident expression of its specific triat (major effect) and less evident effects of its
other triat (secondsry effect).
Most children with cystic fibrosis have frequent lung infections and.pdf
1. Most children with cystic fibrosis have frequent lung infections and digestive difficulties. Some
people have mild cases, with onset of minor respiratory problems in adulthood. Some men with
cystic fibrosis only exhibit the symptom of infertility. Which exception to Mendelian laws of
inheritance best explains these symptoms?
1.) incomplete dominance
2.) pleiotropy
3.) epistasis
4.) codominance
5.) overdominance
Solution
2. Pleiotropy.
Some genes influence not only the triats generally associated with them but also many other
triats. The multiple effect of a gene is called pleiotropy and gene having multiple phenotypic
effects is called pleiotropic gene.
Pleiotropic genes may not have equal influecne on all triats they control and these genes may
cause a very evident expression of its specific triat (major effect) and less evident effects of its
other triat (secondsry effect)
