Epistatis, Chi - Squared

Question 1

What is epistatis?

Answer 1

This is when the allele of one gene masks or affects the expression of another in the phenotype

Question 2

Give one example of epistatis.

Answer 2

Notes

Question 3

What are the two types of epistatis?

Answer 3

Genes affecting the expression of other genes

When genes act in a sequence by determining the enzymes in a biochemical pathway
- In this, dominant alleles code for functional enzymes and recessive alleles code for non functional enzymes, preventing metabolic pathways

Question 4

What is chi - sqaured?

Answer 4

Tests the null hypothesis and states if there is a significant difference between sets of observations

Question 5

What are the conditions for chi - sqaured?

Answer 5

• sample size is large
• discrete categories
• experimental data
• raw data

Question 6

What is the equation for chi - squared?

Answer 6

sum of (observed number - expected number)2/ expected number

Question 7

What do you do after you calculate chi squared?

Answer 7

read of the chi - squared distribution table using degrees of freedom
degrees of freedom = number of classes - 1
use the statistical value of 5%
If the critical value is less than the calculated value then the null hypothesis can be rejected and the alternative hypothesis can be accepted