chapter 21

About how many nucleotide bases are there in the human diploid genome?

7 billion

Genomics is:

the study of whole genomes

When you shatter a chromosome into small fragments, then DNA sequence all the fragments, then use a computer to align and overlap all the fragments to reconstruct the original full DNA sequence, this is called:

shotgun sequencing

Which of the following is basically always true?

prokaryotic genomes have higher gene density than eukaryotic genomes

About how many genes do humans have?

about 20,000-30,000

What percent of your genome is expressed as genes (i.e. translated into proteins or transcribed into functional RNAs)?

~1.5%

The human genome is mostly:

repetitive DNA

What did Barbara McClintock discover?

transposition

Transposable elements mean that:

• genomes are constantly re-arranging

• DNA sequences are not stable

• DNA is dynamic

• You are genetically different today than you were yesterday

There are many copies of some genes and only 2 copies (one from each homologous chromosome) of some genes.  Which is a gene family that you have hundreds to thousands of copies of?

ribosomal RNA

Which of the following processes can contribute to the evolution of new genes?

• transposition

• exon shuffling

• exon duplication

• point mutations

Homologous recombination is a natural process in meiosis, when, for example, homologous sections on your maternal and paternal chromosome #8 exchange.  When might you see a section of chromosome 8 exchanged with a part of chromosome 12?

if you are comparing two different species

What do homeotic genes control?

developmental patterns

Which of the following is NOT true about transposons and retrotransposons?

one is synthesized 5' to 3' while the other is synthesized 3' to 5'

When parts of 3 existing genes combine to form a new gene, this is called:

exon shuffling

bioinformatics

application of mathematics and computer science to store, retrieve, and analyze biological data

cytogenetic map

A map of a chromosome that locates genes with respect to chromosomal features distinguishable in a microscope.

linkage mapping

the mapping of genes or other genetic sequences along a chromosome by analyzing the outcome of crosses

physical mapping

the mapping of genes or other genetic sequences using DNA cloning methods

DNA sequencing

Determining the exact order of the base pairs in a segment of DNA.

There are 2 main types of transposable elements in your genome: transposons and retrotransposons. What is the difference?

a.
retrotransposons involve an RNA intermediate while transposons do not
b.
retrotransposons come from retroviruses while transposons do not
c.
transposons jump forward in the DNA while retrotransposons jump backward in the DNA
d.
Barbara McClintock used a retrotransposon to travel back in time to get a Nobel Prize
e.
transposons jump around in DNA while retrotransposons do not

retrotransposons involve an RNA intermediate while transposons do not

The amount of the human genome that consists of gene coding exons is

a.100%
b.1.5%
c.25%
d.< 1%
e.5%

1.5%

Which of the following correctly describes the shotgun technique for sequencing a genome?

a.
making genome fragments, matching them back to the genome, and sequencing the paired sequences
b.
physical mapping followed immediately by sequencing
c.
sequencing the genome in one continuous reaction
d.
genetic mapping followed immediately by sequencing
e.
making random genome fragments, followed by sequencing, then ordering

making random genome fragments, followed by sequencing, then ordering

Which of the following is the best description of a genome:

a.
all of the exons in an organism
b.
all of the transcribed DNA in an organism
c.
all of the genes in an organism
d.
all of the DNA in an organism
e.
all of these are good descriptions of a genome

all of the DNA in an organism

If an organism A has "higher gene density" than organism B - what does this mean?

a.
organism B has more genes
b.
organism A has higher gene expression
c.
organism A has a higher ratio of genes to "other" DNA
d.
organism A sinks faster in water
e.
organism A has more genes

organism A has a higher ratio of genes to "other" DNA

the human genome project

An international collaborative effort to map and sequence the DNA of the entire human genome. it fostered development of faster, less expensive sequencing techniques

whole-genome shotgun approach

the whole genome is cut into many small, overlapping fragments that are sequenced; computer software then assembles the genome sequence.

gene annotation

The identification of protein coding genes within DNA sequences in a database

systems biology

scientists use the computer-based tools of bioinformatics to compare genomes and study sets of genes and proteins as whole systems

Proteomics

study of the structure and function of proteins in the human body

genomes vary in _________

size, number of genes, and gene density

multicellular eukaryotes have a lot of________

noncoding dna and many multigene families

only 1.5% of genones code for proteins, rRNAs and tRNAs the rest is _____________

noncoding DNA including psuedogenes and repetitive DNA of unknown function

pseudogenes

former genes that have accumulated mutations and are nonfunctional

Repetitive DNA

Nucleotide sequences, usually noncoding, that are present in many copies in a eukaryotic genome. The repeated units may be short and arranged tandemly (in series) or long and dispersed in the genome.

the most abundant type of repetitive DNA in multicellular eukaryotes consists of ____________

transposable elements and related sequences

transposable elements

mobile pieces of DNA that can copy themselves into entirely new areas of the chromosomes. two types: transposons and retrotransposons

Transposons

(jumping genes) short strands of DNA capable of moving from one location to another within a cell's genetic material

Retrotransposons

Transposable elements that move within a genome by means of an RNA intermediate, a transcript of the retrotransposon DNA.

simple sequence DNA

A DNA sequence that contains many copies of tandemly repeated short sequences.

STRS

Short tandem repeats used in DNA profiling.

duplication

change to a chromosome in which part of the chromosome is repeated

rearrangement

a change in connectivity of the atoms in a product compared with the connectivity of the same atoms in the starting material

mutation

a random error in gene replication that leads to a change

what can contribute to genome evolution

duplication, rearrangement, and mutation

polyploidy

condition in which an organism has extra sets of chromosomes

evolutionary developmental (evo-devo) biologists

have shown that homeotic genes and some other genes associated with animal development contain a homeobox region whose sequence is highly conserved among diverse species

homeobox

a DNA sequence within a homeotic gene that regulates development in animals