-
What
are the two types of repeated sequences in eukaryotic DNA? What is the
main difference between the two?
(see Table 18-3)
•Tandemly repeated DNA
- •Interspersed repeated DNA
-
What
are the three types of tandemly repeated DNA? What is the relative
difference between them? Which one includes the centromere and telomere
DNA?
- •Satellite DNA: hundred of thousands of repeats of short sequences (5-a few
- hundred bp);
- includes centromere and
- telomere DNA
- •Minisatellite DNA: as many
- as 3,000 repeats of short sequences (10-100 bp); highly variable in the population, a
- type of VNTR (variable number of tandem repeats)
- •Microsatellite DNA: <40 repeats of short sequences
- (1-10 bp); aka
- STR (short tandem repeats), a type of VNTR
-
What
is meant by coding vs. noncoding DNA? Are coding DNA repetitive,
nonrepetitive, or depends on which DNA? (Hint: Are DNA that code for rRNA,
tRNA, and histone proteins repetitive?)
- •Coding DNA: clustered identical tandem
- repeats of DNA that code for rRNA, tRNA, and mRNA for histones
- -Moderately repetitive.
- •Non-coding DNA: interspersed, similar
- sequences of DNA that include LINEs, SINEs, retroviral-like elements, and
- DNA-only transposons
- (transposable or mobile genetic elements)
-
What are
the four types of interspersed DNA?
- include LINEs, SINEs, retroviral-like elements, and DNA-only transposons
- (transposable or mobile genetic elements)
-
What
are LINEs and SINEs? How do they differ? What is an example of each?
- –Long Interspersed Nuclear
- Elements (LINEs): Eg. L1 element
- •>6000 bp long, >500,000 copies, about 20% of human genome
- •L1 sequence encodes a protein
- with reverse transcriptase and endonuclease activity
- –Short Interspersed Nuclear
- Elements (SINEs): Eg. Alu
- sequence
- •~300 bp long, ~1 million copies, about 10% of human genome
-
How
does a retrotransposon move?
- –Retrotransposons - transcribe into RNA, reverse
- transcribe into DNA, make DNA ds, then integrate into genome
-
What
are VNTR and STR?
- VNTR (variable number of tandem repeats)
- STR (short tandem repeats)
-
Know
some facts about the human genome. (What is the haploid size? How many
chromosomes? How many genes? Approximately how many percent encodes for
RNA or protein products and are typically highly conserved? Approximately
how many percent are in other highly conserved sequences such as 5’ and 3’
UTRs, genes for structural and catalytic RNAs, and regulatory DNA?)
-
What
do biologists call DNA with no known function? Are these DNA common or
rare in the human genome?
Junk DNA, COMMON
-
How
similar is the genome between two unrelated individuals?
.3%
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