Genetics Exam 1 Flashcards
What are the different chromosomes for the following species?
Humans
Birds
Crickets
Bees
Humans XY-XX
Birds ZZ-ZW
Crickets X:XX
Bees: Haploid:Diploid
What does a recessive pattern look like in a phenotype… Draw it out
Unaffected heterozygous parents with some affected offspring
What are dominant patterns patterns in Pedigrees?
Effected Patterns with non affected off springs
Affected child = affected parents
What is a Loss of Function Allele
- Recessive
- Referred to as knockout
- Wild type compensates for recessive loss of function trait
What are the characteristics of a Gain of Function Mutation
- Dominant trait
- Gaining an abnormal function
What are the characteristics of a Dominant Negative Mutation
- Dominant
- When a mutant allele antagonizes the wild type
What are the characteristics of Haploinsuffiencies
- Dominant
- Loss of function mutation but wild type CANNOT compensate
What describes Incomplete Penetrance?
How does this look on a pedigree?
- When a dominant allele does not effect phenotypic outcome
- Seen in dominant traits skipping over generations
Incomplete Dominance
The heterozygote offspring exhibits is intermediate between phenotypes
Ratio 1:2:1
Over Dominance
Known as the “heterozygote advantage”
Heterozygotes are different and often offer advantages over homozygous individuals
Sickle Cell is an example of……
Over Dominance: “heterozygote advantage”
Codominance
Both alleles are expressed and and affect phenotypes
Blood type AB is an example of….
Codominance
Describe Complementation
Two affected parents have unaffected offspring
Mutations are present in separate genes which produces a wild type
How can you determine if genes are on the same gene (allelic) using a complementation table?
Negative sign (-) means that genes are allelic
How can you determine complementation groups using a complementation table?
Complementation groups are genes that do not complement one another and therefore effect the same gene
Epistasis
This is when a gene mask the phenotypic effects
If there is a recessive homozygous trait, masking occurs
Ratio- 9:7
What describes Pleiotropy
Where a mutation/gene effects multiple traits
Describe what Modifiers are
Alleles of one gene alters the phenotype of another genes
Ex: Mice ( black x brown x white )
9:3:4
What is Redundancy?
Phenotype is only affected when both traits are homozygous recessive.
Lethal Alleles
When a certain combination leads to death
2:1
How can you utilize the CHI Squared Test to test the validity of a test cross?
x^2
= Sum (obs-exp)^2/exp
What is linkage?
When genes are close on a chromosome and travel together as a result
What are the two cross over types?
Single Crossover
Double Crossover
