Exam 18: Genomics: Genetics From a Whole-Genome Perspective

It has been predicted that genes may be involved in smoking initiation and/or current smoking behavior.Previously,large twin and family studies have provided evidence of this and an estimate of heritability (genetic contribution)of 37-55% for initiation and 46-59% for current smoking,depending on gender.A large group of researchers from several institutions composed a pathway-or-systems-based series of studies including SNP analysis,cellular location and protein interaction,replication with other samples,statistical analysis,and bioinformatics.What is a likely result?

What is the purpose of the two-hybrid system?

A gene in a sheep-like species has been found to differ from that in related species by the inclusion of a variable number of tandem repeats of a short sequence.These repeats or duplications arise from what process?

To study the maximum amount of genome diversity in the human species,which of the following provides the most information?

Transcomplementation is a name sometimes given for a test to see whether a gene from one organism can "rescue" a loss-of-function mutant of a different organism with a homologous gene.To which of the following processes might this term apply?

If an entire genome is fragmented and then a large number of pieces are sequenced,the approach is known as the ________ approach.

Scientists studying the causes of a type of progressive hearing loss known as otosclerosis want to identify the genetic contribution to the disorder.By which of the following are they most likely to find a causative gene or genes?

A report of a newly identified syndrome in families of the Old Order Amish showed that the lethal condition that resulted from numerous,multisystem abnormalities is inherited as an autosomal recessive.SNP-based mapping showed that a portion of a region on chromosome 6p,namely the ICK gene (intestinal cell kinase),was homozygous in all autopsied patients but heterozygous in normal members of the affected families.The mutation seems so far to be specific only to the Amish.Which of the following would be a reasonable next step in studying this mutation?

A genome sequence is considered to be complete when all its ________ sequences are included,as well as reasonable amounts of repetitive sequences.

Now that small molecular-level deletions and subtle chromosomal rearrangements can be discovered using advanced cytogenetic techniques and microarrays,disorders whose causes had not previously been known can have their basis identified.However,since most of these are not widely publicized,being individually rare,it has been difficult to identify patients with shared chromosomal abnormalities who share phenotypic features.A new database,known as DECIPHER,is now available to search for patients with like phenotypes and/or like chromosomal abnormalities.If you are the clinical geneticist who has a patient whose data is entered into this database,suggest three or more ways in which this could be useful either to you or to the patient.

In looking for a gene responsible for albinism in humans,a group of researchers decided that at least one form of this condition was due to a lack of the enzyme tyrosinase.With this decision as a starting point,which of the following series of steps was most feasible?

If a gene product is not a protein but a noncoding RNA,the sequence might be initially hypothesized from comparative genomics but must be confirmed how?

Often,in the absence of experimental data,computerized algorithms are used to predict gene structures from large sequences.What is this approach known as?

The whole-genome shotgun approach (WGS)was first used on which eukaryotic model organism?

Recombination between two Alu elements results in deletions.In humans these have often been associated with specific disorders.In a recent study,researchers compared Alu recombination-mediated deletions of humans and chimpanzees.They identified 492 human-specific deletions of this type.Why is this finding important?

When Warnecke and colleagues were looking for genes that are involved in the digestion of lignocellulose by termites,they needed genes

Under what circumstances is a metagenomic analysis preferable to analysis of a gene or genes from a single species?

Which of the following describes genome tiling arrays?

Interspecific genome studies show us conserved sequences,but intraspecific comparisons identify what?

Celiac disease (CD)is a common,usually inherited human disorder of intestinal inflammation that is triggered by eating gluten,a major protein in wheat and other cereal grains.It is the most frequent food intolerance.One of the three genes involved is for SH2B3,a protein involved in innate,nonspecific immune response to bacterial pathogens.Celiac sufferers frequently have a particular allele of this gene.It is so common that which of the following might be hypothesized?