Genetics last quiz (ch 7, 22)

Most microbes in the world are .

"unculturable" - they cannot be grown in the lab

The most common in humans is

(CA)n, where n is anywhere from 5-50 repeats.

Biotechnology: Microorganisms can synthesize a vast array of useful chemicals example

- Example: new antibiotics for bacterial infections

This microsatellite is found about every____ in the human genome.

10,000 bases

In humans there are _____ linkage groups, plus an X linkage group, and a Y linkage group.

22 autosomal

In crosses involving flower color and pollen length in the sweet pea, the researchers noticed that the offspring did not display a ----- phenotypic ratio as expected from a ______

9:3:3:1 two-factor cross (Figure 7.1).

metagenome can be?

Can be analyzed similarly to the study of a single genome.

Creighton and McClintock Showed That Crossing Over Produced New _____

Combinations of Alleles and Resulted in the Exchange of Segments Between Homologous Chromosomes

Morgan Provided Evidence for the Linkage of X-Linked Genes and Proposed That

Crossing Over Between X Chromosomes Can Occur

The Imprinting of Genes and Chromosomes is a Molecular Marking Process That Involves

DNA Methylation

Genome-sequencing projects have the ultimate goal of determining the sequence of

DNA bases of the entire genome of a given species.

Innovations in DNA Sequencing Have Made It

Faster and Less Expensive

____ by crossing over can produce new combinations of alleles on chromosomes (Figure 7.2).

Genetic recombination

The Human Genome Project Was the

Largest Genome-Sequencing Project in History

Linkage Mapping Commonly Uses Molecular Markers Called

Microsatellites

Linkage Mapping Can Use

Molecular Markers

The Biological Significance of Imprinting Is

Not Well Understood

c.?

Overlaps between the fragments allow the researchers to put them in order (Figure

RFLP vs microsatellites

RFLPs utilize restriction digests and Southern blots, while microsatellites use PCR

nonrecombinant cells

The cells that contain the original combination of alleles are called

The first direct evidence that different genes are physically located on the same chromosome was provided by

Thomas Hunt Morgan

Bateson and Punnett Discovered

Two Characters That Did Not Assort Independently

Restriction fragment length polymorphisms (RFLPs)

are produced by digesting chromosomal DNA with a restriction enzyme. This produces fragments of different lengths. These lengths may vary between individuals. a. This variation is called a polymorphism.

Genes that are far apart on a chromosome may due to crossing over.

assort independently

The advantage of shotgun DNA sequencing is

avoiding the time and expense of mapping.

There are many practical reasons to study metagenomics.

b. Agriculture: Metagenomic analysis of soil samples reveals astonishing complexity of soil microorganisms, which may improve agricultural yields.

he first genome to be entirely sequenced was that of the

bacterium Haemophilus influenzae H. influenzae causes respiratory illnesses and bacterial meningitis

The _____ consists of two homologous chromosomes with a pair of sister-chromatids each.

bivalent chromosomes

His experimental proof used three traits: .

body color, eye color, and wing shape

There are many practical reasons to study metagenomics.

e. Global change: Microorganisms carry out half the photosynthesis on Earth and cycle elements such as carbon, phosphorus, and nitrogen.

With three traits assorting independently, it was expected that there would be ____ phenotypic classes, each in equal proportion.

eight

2. In the 1980s and 1990s Norman Pace showed that

environmental samples had a huge variety of microbial genes that could be PCR'd from unculturable microbes.

There are many practical reasons to study metagenomics.

f. Identification of viruses: Environmental samples are analyzed to identify human viruses.

Morgan explained this observation by hypothesizing that genes that are ____ cross over than genes that are close together

far apart are more likely to

There are many practical reasons to study metagenomics.

g. Aquatic biology: Samples from rivers, lakes and oceans reveal great complexity of microbial communities.

Technology innovations have greatly reduced the cost of

genome sequencing.

Chromosomes are often called ____ since the genes on a chromosome are physically connected to one another.

linkage groups

Imprinting has been identified in many (Table 6.6).

mammalian genes

The Haig hypothesis states that

maternal imprinting tends to inactivate genes associated with increased embryonic growth, while paternal imprinting tends to inactivate genes associated with decreased embryonic growth.

- Also, 1800+ new species of _______s were identified.

microbes

Regions of DNA that do not encode genes can be used as _____

molecular markers. A molecular marker is a segment of DNA that is found at a specific site along a chromosome.

how many genes does a chromosome consist of?

more than one gene, typically in the hundreds or thousands.

They used these abnormalities to trace the

movement of alleles for kernel color and the texture of the kernel endosperm.

Bateson and Punnett were the first researchers (1905) to demonstrate that

not all traits assort independently.

Like RFLPs, microsatellites that have length polymorphisms allow researchers to follow their transmission from ______. PCR amplification of microsatellites can be used with genetic analysis of human pedigrees, as shown in Figure 22.6.

parent to offspring

Morgan's results (Figure 7.3) indicated that the _____ Morgan correctly suggested that these three traits are found on the ______

parental combinations were the most prevalent in the offspring. X chromosome and are inherited together as a unit.

The length of the particular microsatellite may be _____

polymorphic.

Crossing over during ____ may alter linkage of genes.

prophase I of meiosis

In their work they identified two chromosomal abnormalities that allowed them to

track the movement of specific chromosomes during meiosis.

Genes that are close together tend to be ____ from parent to offspring as a group.

transmitted

When geneticists follow traits they rely upon ?

two-factor and three-factor crosses.

Morgan studied

X-linked patterns of inheritance.

Morgan suggested three hypotheses to explain his results:

a. All three genes are located on the same chromosome (the X chromosome). b. Crossing over produces new combinations of alleles. c. The likelihood of crossing over depends on the distance between the two genes.

Motivation behind genome-sequencing projects comes from a variety of sources:

a. Basic research scientists can greatly benefit from a genome sequence. b. The need to identify causes of human disease.

Pyrosequencing is a

a. DNA samples are broken down into small fragments, which are then linked to short oligonucleotides called adaptors on the 5' and 3' ends. b. The DNA is denatured into single strands and attached to beads via the adaptors. c. The beads are emulsified so there is only one bead per droplet. d. The beads are deposited into a picotiter plate. e. The sequencing reagents are added, and solutions containing A, T, G, or C are sequentially flowed into the wells. f. If a nucleotide has been incorporated in the sequencing reaction, pyrophosphate is released, triggering a series of enzymatic reactions which results in light being given off that is detected by a camera.

There are many practical reasons to study metagenomics. (7)

a. Human medicine: Metagenomics is used to characterize populations of microorganisms in the mouth and intestines, and find changes associated with disease.

6. The Global Ocean Sampling Expedition was started in 2003 by J. Craig Venter and colleagues. They did what?

a. They sampled the microbial poplation of the nutrient-limited Sargasso Sea because it has a relatively simple population of microbes.

The goals of the Human Genome Project were:

a. To obtain a genetic linkage map of the human genome. b. To obtain a physical map of the human genome. c. To obtain the DNA sequence of the human genome. d. To develop technology for the management of the human genome information. e. To analyze the genomes of other model organisms. f. To develop programs focused on understanding and addressing the ethical, legal, and social implications of the results obtained from the Human Genome Project. g. To develop technological advances in genetic methodologies.

Genomic DNA is broken into smaller DNA fragments about.

about 1500 bp or longer in length

Part b?

about 1500 bp or longer in length

There are many practical reasons to study metagenomics.

c. Bioremediation: Microorganisms in soil and water help decomposition of pollutants in the environment, and metagenomics may identify the most useful microorganisms.

Motivation behind genome-sequencing projects comes from a variety of sources:

c. Genomes of agriculturally important species will lead to the development of new strains of livestock and crops that have improved traits. d. Understanding evolutionary relationships among living species, which is called comparative genomics.

Missing links in the genome can be sequenced later using mapping methods such as

chromosome walking.

A metagenome is a

collection of genes from a particular environmental sample

5. Researchers must decide how many fragments to sequence to get a _____.

complete genome Using the equation P = e-m b. P is the probability that a base will be left unsequenced . e is the base of the natural logarithm d. m is the number of bases sequenced divided by the total genome size

Metagenomics is the study of a

complex mixture of genetic material obtained from an environmental sample.

they worked with ____ as an experimental system

corn

They suggested that their traits were

coupled to one another in some manner.

For offspring that did not contain the parental combinations, Morgan suggested that there was

crossing over between the homologous X chromosomes.

There are three ways to determine the organization of DNA regions.

cytogenic, linkage, physical mapping

There are many practical reasons to study metagenomics.

d. Biotechnology: Microorganisms can synthesize a vast array of useful chemicals.

Creighton and McClintock are responsible for providing the first direct evidence that crossing over is associated with

genetic recombination.

linkage

indicate two genes that are located on the same chromosome.

4. A genetic map, or chromosome map,

is a chart that described the relative locations of genes or other DNA segments along a chromosome. Each gene or DNA segments has a specific locus on a chromosome.

The cells that contain the new allelic combinations are called _____. T

recombinant cells

a. Cytogenetic mapping (cytological mapping)

relies on the localization of gene sequences within chromosomes that are viewed using a microscope.

But researchers waste effort sequencing the

same region of DNA over and over again.

Using PCR primers, a particular microsatellite may be amplified. This is called a

sequence-tagged site (STS).

Since 1995, over 300 prokaryotic genomes and 100 eukaryotic genomes have been ____

sequenced.

Samples revealed

several hundred new proteorhodopsin light harvesting genes that may help us understand their role in energy metabolism under low nutrient conditions.

2. The most efficient and inexpensive way to sequence genomes is by

shotgun sequencing.

High-throughput sequencing is

the ability to rapidly sequence large amounts of DNA, and is common today because of advances in sequencing automation and parallel sequencing platforms.

The term mapping refers to

the experimental process of determining the relative locations of genes or other segments of DNA along individual chromosomes.

Their experimental system indicated that the process of crossing over was responsible for

the generation of genetic recombinations and that this was due to

An imprinting control region (ICR) is located near ____, and regulates the _______

the imprinted gene transcription of the imprinted gene.

Genomic imprinting of some genes is known to involve differentially methylated regions. The regions are methylated in (Figure 6.9).

the oocyte or sperm, but not both

- They ran 7.7 million sequencing runs, yielding 6 billion bp of DNA sequence, and discovered that most of the DNA sequences were ____

unique!

The chromosomes consisted of

unusual staining patterns or translocations.

genetic map

used to diagram the order of genes along a chromosome

b. Linkage mapping

uses the frequency of recombination to determine the relative spacing of genes on a chromosome.

c. Physical mapping

utilizes DNA cloning techniques to determine the location and distance between genes in nucleotide base pairs.