Genetic Linkage and Mutations

Thirty practice flashcards based on genetic linkage, mutations, and pedigree analysis concepts.

In genetic analysis, what does 'D' typically represent in alleles?

The hypothetical disease allele.

What would a positive LOD score indicate in linkage analysis?

Evidence for linkage between genetic markers.

What phenomenon occurs when a disease manifests earlier with successive generations?

Anticipation.

How is a recombinant gamete defined in the context of meiosis?

A gamete that has undergone recombination between loci for the condition and the marker.

What role do 'marker alleles' play in determining genetic disorders?

They help track the inheritance of a disease gene within families.

What is a key characteristic of dynamic mutations?

They occur due to expansions of short tandem repeats.

How does homozygosity in a pedigree suggest the presence of recessive disease genes?

All affected individuals show the same homozygous alleles inherited by descent.

What is meant by 'non-informative meiosis'?

Meiosis that does not provide distinct information about inheritance due to homogenous gametes.

Which sequence is typically associated with Fragile X syndrome?

CGG repeat in the FMR1 gene.

What is the difference between loss of function and gain of function mutations?

Loss of function typically leads to reduced gene activity, while gain of function involves increased or novel gene activity.

What are LOD scores used for in the context of genetic mapping?

To assess the probability that a given genetic trait and marker are linked.

What technique can be used to detect CAG repeat expansions in Huntington disease?

PCR and polyacrylamide gel electrophoresis.

What does 'haploinsufficiency' mean?

A condition where one functional copy of a gene is insufficient for normal function.

What does a negative LOD score indicate?

Significant evidence against linkage of genetic markers.

Which type of inheritance is commonly seen in dynamic mutations?

Autosomal dominant inheritance.

What is a common cause of tumors related to gain of function mutations?

Overexpression or modification of certain genes.

What binding is affected in the genetic analysis of Huntington's disease?

CAG repeat expansion in the HTT gene.

In the context of dynamic mutations, what is the significance of expanded repeats?

They can lead to instability and associated diseases.

What does 'N' and 'R' signify in pedigrees during genetic analysis?

N refers to non-recombinant and R refers to recombinant alleles.

What is the primary focus of linkage analysis in genetics?

Identifying the distance between a genetic marker and a disease gene.

What does the term 'allelic heterogeneity' refer to?

Different mutations within the same gene that can cause the same phenotype.

What genetic mapping technique utilizes multiple markers and their LOD scores?

Two-point linkage analysis.

What genetic mechanism is often involved in cancers?

Gain of function mutations.

What factors are considered in exome sequencing to identify disease genes?

Genetic models, mutation types, databases, and predictions of variant effects.

In linkage analysis, what is necessary to claim that a meiosis is 'phase-known'?

Clear association deduced between the mutation and marker alleles.

What does the presence of non-recombinant sperm signify in pedigree analysis?

It reveals that there was no crossover between the condition locus and the marker.

What implications do dynamic mutations have for genetic counseling?

They can suggest increased disease risk for offspring in successive generations.

What is an example of a condition showing anticipation?

Fragile X syndrome.