Genetics Flashcards
What is a mono hybrid cross?
A cross between individuals that only differ one characteristic
What is a pedigree analysis?
Study of the inheritance pattern of human genetic diseases
What is a dihybrid cross?
Cross between 2 individuals that express different trait from 2 characteristics
What states the law of segregation?
Paired unit factors must be segregate equally into gametes such that offspring have an equal likelihood of inheriting either factor
What states the law of indépendant assortment?
Genes do not influence each other regard to the sorting of alleles into gametes such that
What is epistasis?
When two genes interact with each other
*Phenotypic of one gene affects that of another
What is pleiotropy?
When one gene is able to affect multiple phenotypic characters (*1 genes = lots of effect)
What is polygenic (continuous variation)?
Many genes interact with each other and also with the environment for one trait
*A single phenotypic character is affected by two or more genes
What is the principle of multiple alleles?
Gene can have multiple version (*«dosage» of genes)
What is codominance?
When BOTH alleles are equally expressed and simultaneously expressed
*both phenotypes expressed in heterozygous
What is incomplete dominance?
A combination of two alleles that creates a new phenotype
What is complete dominance?
Condition where the dominant allele completely masks the effect of the recessive allele
What is complete dominance?
Condition where the dominant allele completely masks the effect of the recessive allele
What is aneuploidy and how it rise to genetic variation?
Genetic disorder where the total number of chromosomes doesn’t equal 46
Rise to variation since it inherit differences between generations
Most of the time, what is the cause of genetic conditions?
Caused by recessive alleles that become non-functional
Does genetic conditions can be caused by dominant genes?
Yes
What is the ultimate goal of the test cross?
To distinguish the Dominant phenotype
What is a X-linked?
Gene only present on the X chromosome
Why recessive X-linked traits are more frequent in males?
Cause they only need to express on their only X allele to represent this traits
What are sec-linked traits?
Gene that are located on a sex chromosome
What is linkage?
Genes that re close together not often get seperated during crossover — they are linked
When genes are never linked, what does it means?
That they are far apart
What is the difference between sex linkage and linkage?
Sex linkage is when a gene is located on sex chromosome while linkage is when autosome gene are close together
What is the default development pattern in human?
Female
What are Barr bodies?
Only one X chromosome is necessary for normal development
When an X chromosome is inactivated in female they are visible as barr body
What is DNA methylation?
When we add a methyl group onto the inactivated X chromosome so it is prevented from transcribing
What is the principle of non-junction?
Chromosome can end up in the wrong cell during meiosis — gamete with an extra chromosome
What is the effect of having an extra X or Y chromosome?
Little effect only can reduce fertility
What is the main cause of chromosome abnormalities?
Mistake during meiosis (ex: inversion — chromosome are not properly aligned)
Why being heterozygous is the best?
Since it reduces the chance of the offsprings to inherit two copies of the recessive allele so reduce the chance of genetic disease
What are microsatellites?
A region of DNA with many STRs
What are two possible ways to fix genetic diseases?
1-genetic engineering
2-gene editing
What is the main function of microsatellites in real life?
Distinguish one person DNA from another persons DNA
What is the main function of CRISPR/CAS9?
To target and cut up the viral DNA taking it into our genome so we can recognize the virus if it reinfects
What are the 5 main steps of CRISPR?
1-Taking part of their viral DNA into their genome
2-Use this sequence to make matching RNA sequence
3-Target viral DNA + attach nuclear
4-cuts out the viral DNA
5-Cut DNA is then repaired
Why gene editing is a way to solve genetic disease?
Since we can cut mutated alleles and replace them with normal alleles
What are the two ways CRISPR can be used?
1-Cas9 cuts DNA and a new sequence is inserted
2-Cas9 DONT cut the DNA — it attaches to a repressor, activator or marker
