Chapter 9 - Molecular Genetic Techniques and Genomics

Protein families

Protein families

________ are thought to arise by two different evolutionary processes, gene duplication, and speciation.

S cerevisiae

In ________, cell division occurs through a bidding process, and the size of the bud, which is easily visualized by light microscopy, indicates a cells position in the cell cycle.

Libraries

________ constructed for the purpose of screening among yeast gene sequences usually are constructed from genomic DNA rather than cDNA.

Geneticists

________ commonly refer to the numerous naturally occurring genetic variants that exist in populations, particularly human populations, as alleles.

experimental organism

The procedures used to identify and isolate mutants, referred to as genetic screens, depend on whether the ________ is haploid or diploid and, if the latter, whether the mutation is recessive or dominant.

plaque

Each ________ arises from a single recombinant phage, all the progeny λ phages that develop are genetically identical and constitute a clone carrying a cDNA derived from a single mRNA; collectively they constitute a λ cDNA library.

RFLPs

________ arise because mutations can create or destroy the sites recognized by specific restriction enzymes, leading to variations between individuals in the length of restriction fragments produced from identical regions of the genome Linkage Studies Can Map Disease Genes with a Resolution of About 1 Centimorgan.

haploid yeast cells

In ________, essential genes can be studied through the use of conditional mutations.

Mice

________ carrying a germ- line knockout may have defects in numerous tissues or die before the developmental stage of interest.

Integration

________ most likely is accomplished by mammalian enzymes that function normally in DNA repair and recombination.

Epitope Tagging

________: In addition to their use in producing proteins that are modified after translation, eukaryotic expression vectors provide an easy way to study the intracellular localization of eukaryotic proteins.

neutral pH

Near ________, DNA molecules carry a large negative charge and therefore move toward the positive electrode during gel electrophoresis.

diploid organisms

In ________, phenotypes resulting from recessive mutations can be observed only in individuals homozygous for the mutant alleles.

Gene

________- targeted knockout mice are generated by a two- stage procedure.

Genetic traits

________ that segregate together during meiosis more frequently than expected from random segregation are controlled by genes located on the same chromosome.

Human geneticists

________ used two different approaches to identify the many genes associated with retinitis pigmentosa.

DNA

In some cases, a(n) ________ library can be screened for the ability to express a functional protein that complements a recessive mutation.

common method

A(n) ________ for visualizing separated DNA bands on a gel is to incubate the gel in a solution containing the fluorescent dye ethidium bromide.

PCR

The ________ depends on the ability to alternately denature (melt) double- stranded DNA molecules and renature (anneal) complementary single strands in a controlled fashion.

Haploid cells

________ with a disruption in all four redundant Hsc70 genes were non- viable unless the cells carried a vector containing a copy of the Hsc70 gene that could be expressed from the GAL1 promoter on galactose medium Specific Genes Can Be Permanently Inactivated in the Germ Line of Mice.

Transient Transfection

________: The simplest of the two expression methods, called ________, employs a vector similar to the yeast shuttle vectors described previously.

Plasmids

________ are circular, double- stranded DNA (dsDNA) molecules that are separate from a cells chromosomal DNA.

somatic cells

Like ________, premeiotic germ cells are diploid, containing two homologs of each morphologic type of chromosome.

Suppressor Mutations

________: The first type of analysis is based on genetic suppression.

Recessive Lethal Mutations

________ in Diploids Can Be Identified by Inbreeding and Maintained in Heterozygotes.

Stable Transfection

________ (Transformation) If an introduced vector integrates into the genome of the host cell, the genome is permanently altered and the cell is said to be transformed.

Restriction fragment length polymorphisms

________ (RFLPs) were the first type of molecular markers used in linkage studies.

genetic diseases

Human ________ that result from a mutation in one specific gene exhibit several inheritance patterns depending on the nature and chromosomal location of the alleles that cause them.

short palindromic sequences

Restriction sites commonly are ________; that is, the restriction- site sequence is the same on each DNA strand when read in the 5 → 3 direction.

Geneticists

________ usually strive to begin breeding experiments with strains that are homozygous for the genes under examination.

diploid organism

Since mutagenesis in a(n) ________ typically changes only one allele of a gene, yielding heterozygous mutants, genetic screens must include inbreeding steps to generate progeny that are homozygous for the mutant alleles Complementation Tests Determine Whether Different Recessive Mutations Are in the Same Gene.

Geneticists

________ exploit the normal life cycle of an organism to test for the dominance or recessivity of alleles.

diploid organisms

Since ________ carry two copies of each gene, they may carry identical alleles, that is, be homozygous for a gene, or carry different alleles, that is, be heterozygous for a gene.