Why was mapping the Huntington's disease gene using RFLP markers a major breakthrough in the 1980s?
Explanation
The mapping of the Huntington's disease (HD) gene was a pivotal moment in human genetics. It demonstrated the power of using anonymous DNA markers (RFLPs) to find the chromosomal location of a disease gene even when nothing was known about the gene itself. This success paved the way for mapping many other human disease genes.
Other questions
How does the concept of linked genes relate to Mendel's Law of Independent Assortment?
What is the primary mechanism that allows for the independent assortment of genes located on the same chromosome?
In a dihybrid testcross involving linked genes, which classes of offspring are expected to be the most numerous?
What is the unit of genetic distance derived from recombination frequencies, as pioneered by Alfred Sturtevant?
In a Drosophila dihybrid testcross for wing size and eye color, the F2 generation consisted of 395 Long red, 225 Long white, 247 miniature red, and 382 miniature white offspring. The parental phenotypes were miniature white and Long red. What is the calculated recombination frequency?
What is the maximum observable recombination frequency between two genes in a two-point testcross?
In a three-point testcross, how do you identify the offspring that resulted from a double crossover event?
In a three-point testcross in mice, the trihybrid parent has the genotype AbC/aBc. The two rarest offspring classes are abC and ABc. Based on this information, what is the correct order of the three genes on the chromosome?
What is the term for a group of SNPs or other molecular markers that are located close together on a chromosome and tend to be inherited as a block?
What is the primary purpose of a Genome-Wide Association Study (GWAS)?
What is a 'molecular marker' in the context of genetic linkage analysis?
What does a Manhattan plot, as used in GWAS, visually represent?
In a three-point testcross for genes A, B, and C, you calculate the following recombination frequencies: A-B is 25 percent, B-C is 32 percent, and A-C is 10 percent. What is the correct map of the chromosome?
Why are pedigree analyses of traits like the ABO blood group particularly useful for human linkage studies, as demonstrated with Nail Patella Syndrome?
What is the relationship between paralogs and pseudogenes?
In the context of constructing a chromosome map from multiple two-point crosses, why is it recommended to always use the shortest 'steps' to build the map?
What is the primary advantage of using a three-point testcross over a two-point testcross for gene mapping?
In a hypothetical pedigree tracking Nail Patella Syndrome (NPS) and ABO blood type, almost all family members with NPS also have blood type B. One individual in generation III has NPS but blood type A. What does this individual represent?
What is the key difference between an ortholog and a paralog?
Which type of DNA polymorphism involves a change in a single base that creates or destroys a restriction enzyme recognition site?
What is meant by the term 'linkage disequilibrium'?
Based on the data for a three-point testcross for genes A, B, and C in mice, the parental classes (AbC and aBc) have the highest numbers of progeny. The double crossover classes (abC and ABc) are the rarest. What can be concluded about gene A?
If a dihybrid testcross for genes E and F (testcross is EeFf x eeff) results in 305 EF, 195 eF, 202 Ef, and 298 ef offspring, what are the parental gametes from the EeFf parent?
Using the offspring data from a dihybrid testcross (305 EF, 195 eF, 202 Ef, and 298 ef), what is the map distance between genes E and F?
What is the primary reason that a two-point testcross can underestimate the true map distance between two distant genes?
What is the meaning of 'synteny' in the context of comparing genomes like those of humans and mice?
In a three-point testcross for genes A, B, and C, the F1 trihybrid (AaBbCc) is crossed with a tester (aabbcc). The offspring data shows that the most numerous progeny are ABC and abc. What were the genotypes of the original true-breeding parents (P generation)?
Thomas Hunt Morgan's work with Drosophila melanogaster was pivotal in establishing the chromosome theory of inheritance. Which key observation led him to hypothesize that certain genes were physically located on the sex chromosome?
If a dihybrid testcross (AaBb x aabb) produces 1000 offspring, and the recombination frequency between genes A and B is 15 percent, how many of the offspring are expected to have a parental phenotype?
What is the phenomenon called where a crossover event in one location on a chromosome can prevent the formation of a second crossover nearby?
If two genes, L and M, have a recombination frequency of 50 percent, what can be concluded about their location?
What type of analysis compares the exomes of family members to identify potential disease-causing mutations?
According to the provided text, what is a key limitation of exome sequencing compared to whole genome sequencing for identifying disease associations?
In the mapping of the Nail Patella Syndrome (NPS) locus, a recombination frequency of about 10 percent was found between the NPS locus and the ABO blood group locus. What does this suggest about their map distance?
In a three-point testcross, the progeny counts are: AbC=38, aBc=42, ABC=16, abc=12, aBC=5, Abc=5, abC=1, ABc=1. The total is 120. What is the recombination frequency between fur (gene B) and whiskers (gene C)?
What does a high -log10(p-value) on the Y-axis of a Manhattan plot signify?
Which statement accurately describes the finding that the Yellowstone wolf population is about 50 percent black, whereas most North American wolf populations are less than 5 percent black?
If a cross between two true-breeding barley strains with short awns produces F1 offspring with long awns, and a self-cross of the F1 produces offspring in a 9 long : 6 short : 1 awnless ratio, what type of gene interaction is occurring?
How many phenotypic classes are possible for a quantitative trait controlled by three cumulative effect QTLs with incomplete dominance?
If a cross between two true-breeding red wheat strains results in an F1 that is also red, and a self-cross of the F1 produces a ratio of 15 red : 1 white offspring, what is the underlying genetic interaction?
What is the result of a complementation test when two individuals with the same recessive mutant phenotype are crossed and their offspring display the wild-type phenotype?
In a series of complementation tests with five strains of white-flowered plants, strain 1 fails to complement strain 3, and strain 2 fails to complement strains 4 and 5. All other crosses produce purple (wild-type) flowers. How many complementation groups (genes) are represented?
What type of DNA polymorphism is defined as a short sequence of 2-6 bases repeated a variable number of times, also known as a microsatellite?
A dihybrid testcross (AaBb x aabb) shows that the parental classes are significantly overrepresented compared to the recombinant classes. What does this indicate about the genes A and B?
If the map distance between gene B and gene C is 0.6 centiMorgans, what is the expected frequency of Aabb genotypes in the progeny of a testcross if the dihybrid parent was produced from AABBCC and aabbcc lines?
In the chapter's discussion of the evolution of genomes, what is the term for structurally related genes within an organism that have arisen from events like gene duplication?
Based on the text, what is the main limitation of using linkage maps created from recombination frequencies to understand the physical structure of a chromosome?
In a three-point testcross progeny analysis, the parental classes are aBc and AbC, and the double crossover classes are abc and ABC. What is the recombination frequency between the two outer genes?
A dihybrid testcross (AaBb x aabb) produces 1000 offspring. The parental phenotypes, AB and ab, account for 900 of the offspring. What is the map distance between genes A and B?