Module 7 - Inheritance Flashcards
What is a genotype?
The genetic constitution of an organism - the alleles an organism has
What is a phenotype?
The expression of the genetic constitution and its interaction with the environment - an organism’s characteristics
How many chromosomes will a diploid and haploid organism have?
Diploid - 2
Haploid - 1
What are the two ways possible genotypes and phenotypes of an offspring can be determined?
Genetic diagram and punnett square.
What type of genetic cross do we use when we are only crossing one type of characteristic?
Monohybrid
What is a codominant allele?
A codominant allele is when both alleles are dominant and therefore both are expressed
If in a monohybrid cross the question asks how many boys/girls will be affected, what do you do?
Multiply the probability by 50% because there is a 50/50 chance of having a boy or girl.
What is it called when there are more than 2 alleles for a gene?
Multiple alleles
What is a dihybrid cross?
This is when we are crossing 2 characteristics
Why are sex chromosomes only carried on the X chromosomes in men and not on the Y chromosome?
The Y chromosome is smaller and so they carry fewer genes
Why are males more likely of expressing a recessive phenotype?
Sex linked genes are on the X chromosome and men only have one x chromosome. This means they will express it even if it is recessive
What is an autosome?
Any chromosome that isn’t a sex chromosome
When are genes said to be linked?
When different genes are located on the same autosome, they are linked. They will stay together during independent segregation.
What makes genes more closely linked?
When they are closer linked on a chromosome
What will split an autosomal linkage?
Crossing over
What is epistasis?
When an allele of one gene masks the expression of the alleles of other genes
What are the two types of epistasis?
Dominant epistatic allele and recessive epistatic allele
What is the phenotypic ratio for a dominant epistatic allele?
9:3:4
What is the phenotypic ratio for a recessive epistatic allele?
12:3:1
What is the chi-squared test?
A statistical test that is used to see if the results of an experiment support the theory
What is the expected result and the observed result?
The expected result is the predicted result and the actual result is the observed result.
What is the null hypothesis?
The Null hypothesis is always that there is no significant difference between the observed results and expected results
When a chi-squared test is carried out and results are not significantly different, what do we say?
Fail to reject the null hypothesis
What is the formula for chi-squared?
The sum of ((O-E)/E)
How do we calculate the expected number of offspring for each phenotype?
(Total number of offspring/total of the ratio) X ratio
How do we calculate if there is any significant difference between the observed result and the expected result?
We compare the x^2 to the critical value
What is the critical value?
This the 5% level of probability that the difference between the expected and observed results is due to chance
What does it mean if the x^2 is higher or equal to the critical value?
There is a significant difference between the expected value and the observed value. The null hypothesis can be rejected.
What does it mean if the x62 is smaller than the critical value?
There is no significant difference between the expected value and the observed value. The null hypothesis has failed to be rejected. The theory is supported.
