A wide-ranging survey of Nicotonia growing in its natural environment recorded a variation in corolla length ranging from 12mm to 47mm with a variance of 36.5. Subsequently, collected seeds were grown in a greenhouse and it was found that the range was now very much lower with most plants having similar corolla lengths and the variance was now only 8.4. a) What is the heritability of corolla length? b) After the plants had grown to maturity and formed seed, seeds were collected from plants with either the shortest and or the longest corollas in the population and planted separately in the greenhouse. When flowers were formed it was found that the variance of the plants with the shortest flowers was now 4.2 while that of the flowers from the longest seeds had become 13.7. Calculate the new values for heritability in the different groups of plants and explain why this difference may arise.
Genetic Variation
Genetic variation refers to the variation in the genome sequences between individual organisms of a species. Individual differences or population differences can both be referred to as genetic variations. It is primarily caused by mutation, but other factors such as genetic drift and sexual reproduction also play a major role.
Quantitative Genetics
Quantitative genetics is the part of genetics that deals with the continuous trait, where the expression of various genes influences the phenotypes. Thus genes are expressed together to produce a trait with continuous variability. This is unlike the classical traits or qualitative traits, where each trait is controlled by the expression of a single or very few genes to produce a discontinuous variation.
A wide-ranging survey of Nicotonia growing in its natural environment recorded a variation in corolla length ranging from 12mm to 47mm with a variance of 36.5. Subsequently, collected seeds were grown in a greenhouse and it was found that the range was now very much lower with most plants having similar corolla lengths and the variance was now only 8.4.
a) What is the heritability of corolla length?
b) After the plants had grown to maturity and formed seed, seeds were collected from plants with either the shortest and or the longest corollas in the population and planted separately in the greenhouse. When flowers were formed it was found that the variance of the plants with the shortest flowers was now 4.2 while that of the flowers from the longest seeds had become 13.7. Calculate the new values for heritability in the different groups of plants and explain why this difference may arise.
Step by step
Solved in 3 steps
