Inheritance

?
  • Created by: Rachelezy
  • Created on: 20-02-20 12:09
Define genotype
The genetic constitution of an organism
1 of 21
Define phenotype
The characteristics of an organism's genetic constitution, combined with interactions with the environment
2 of 21
What is an allele?
Different forms of a particular gene found at the same locus (position) on a chromosome. A single gene could have many alleles.
3 of 21
How many alleles per gene do diploid organisms carry?
Two
4 of 21
What is meant by a dominant allele?
An allele whose characteristics will always appear in the phenotype, whether one or two are present.
5 of 21
What is meant by a recessive allele?
An allele whose characteristics will only appear in the phenotype if a dominant allele is not present, meaning two recessive allele must be present in order for them to appear
6 of 21
What is meant by codominant alleles?
Two dominant alleles that both contribute to the phenotype, either by showing a blend of characteristics or two characteristics seen together.
7 of 21
What is meant by homozygous and heterozygous?
Homozygous = both alleles are either dominant or recessive. (two of the same). Heterozygous = One allele is dominant, the other is recessive.
8 of 21
Define monohybrid inheritance
Where one phenotypic characteristic is controlled by a single gene
9 of 21
What are the stages of creating a genetic diagram
1) Parental phenotype 2) Parental Genotypes 3) Gametes 4) offspring genotypes (draw a Punnett Square) 5) offspring phenotypes
10 of 21
Define dihybrid inheritance
Where two phenotypic characteristics are determined by two different genes present on two different chromosomes at the same time.
11 of 21
What is meant by sex-linkage?
Where an allele is located on one of its sex chromosomes, meaning the expression depends on the sex of the individual
12 of 21
Why are males more likely to express a recessive sex-linked allele?
Most sex-linked alleles are located on X chromosomes. Males then only get one copy of the allele, so will express it even if it is recessive. As females get two of these alleles, it is less likely.
13 of 21
Which parent do males inherit sex-linked characteristics from?
Mother since the Y chromosome only comes from their father. If mother is heterozygous for sex-linked alleles, she is a carrier and may pass the trait on
14 of 21
What is meant by autosomal linkage?
Where two or more genes are located on the same (non-sex) chromosome. In this case, only homologous pair is needed for all four alleles to be present. For genes that are not linked, two homologous pairs are needed
15 of 21
What is meant by epistasis?
Where two non-linked genes interact with one another one either masking or suppressing the other gene
16 of 21
Describe the two types of epistasis
1) Recessive Epistasis - Two homozygous recessive alleles mask expression of another allele. 2) Dominant Epistasis - One dominant allele masks expression of multiple other alleles
17 of 21
What is the chi-squared test?
A statistical test to find out if the difference between the observed and expected results is due to chance or a real effect
18 of 21
What are the criteria for the chi-squared test?
- Data placed in discrete categories - Large sample size - Only raw count data allowed (no percentages) - No data values equal zero
19 of 21
How is chi-squared test performed?
Results in a number which is then compared to a critical value (degrees of freedom) If number is great than or equal to the critical value, we can conclude that there is no significant difference and the results occurred due to chance
20 of 21
How can we use a chi-squared test in relation to this topic?
Can compare expected phenotypic ratios with observed ratios to test understanding of how different genes and alleles are inherited
21 of 21

Other cards in this set

Card 2

Front

Define phenotype

Back

The characteristics of an organism's genetic constitution, combined with interactions with the environment

Card 3

Front

What is an allele?

Back

Preview of the front of card 3

Card 4

Front

How many alleles per gene do diploid organisms carry?

Back

Preview of the front of card 4

Card 5

Front

What is meant by a dominant allele?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all DNA, genetics and evolution resources »