Lesson test: Evidence in the genome

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Evidence in the genome

1.[3p]
Why is a shared error better evidence of common ancestry than a shared correct feature?

Both scribes could copy a correct reading from different sources, but a unique mistake has no cause except a shared exemplar

Correct

Errors are easier to detect than correct features

The answer is: Both scribes could copy a correct reading from different sources, but a unique mistake has no cause except a shared exemplar

Correct features are usually rare

The answer is: Both scribes could copy a correct reading from different sources, but a unique mistake has no cause except a shared exemplar

Errors accumulate faster than correct features

The answer is: Both scribes could copy a correct reading from different sources, but a unique mistake has no cause except a shared exemplar

2.[2p]
About what percentage of the human genome consists of endogenous retrovirus sequence?

CorrectNot quite: 8

3.[3p]
A critic says retroviruses have preferred insertion sites, so shared positions could be coincidence. What answers this without appealing to probability?

Inherited elements share every mutation that arose before the split and sit in identical flanking sequence

Correct

Retroviruses have no preferred sites at all

The answer is: Inherited elements share every mutation that arose before the split and sit in identical flanking sequence

The genome is too large for any site to be hit twice

The answer is: Inherited elements share every mutation that arose before the split and sit in identical flanking sequence

Shared elements are always functional

The answer is: Inherited elements share every mutation that arose before the split and sit in identical flanking sequence

4.[3p]
Why is a broken GULO gene stronger evidence than a working one would be?

A working gene is explained by shared requirements, and a broken one has no functional explanation at all

Correct

Broken genes are rarer than working ones

The answer is: A working gene is explained by shared requirements, and a broken one has no functional explanation at all

A broken gene cannot have been inherited

The answer is: A working gene is explained by shared requirements, and a broken one has no functional explanation at all

Working genes are harder to sequence

The answer is: A working gene is explained by shared requirements, and a broken one has no functional explanation at all

5.[3p]
The descent account predicts that the human and guinea pig GULO pseudogenes carry the same disabling mutations.

True

The answer is: False

False

Correct

6.[3p]
Which features must a human chromosome show if it is a fusion of two ancestral ape chromosomes?

Select all that apply

Degenerate telomere repeats facing head to head somewhere in its middle

Correct

The remains of a second, silenced centromere

Correct

A banding pattern matching two ape chromosomes laid end to end

Correct

A total gene count double that of any other chromosome

The answer is: Degenerate telomere repeats facing head to head somewhere in its middle, The remains of a second, silenced centromere, A banding pattern matching two ape chromosomes laid end to end

7.[2p]
Humans have 23 pairs of chromosomes. How many pairs do chimpanzees, gorillas and orangutans have?

CorrectNot quite: 24

8.[2p]
What is the six-base sequence repeated at vertebrate telomeres?

CorrectNot quite: TTAGGG

9.[3p]
Match each genomic observation to what it is evidence of.

One genetic code across all life
200,000 matching retrovirus sites
A disabled vitamin C gene
Human chromosome 2

two ancestral chromosomes fused in one lineage
descent from a single ancestral population
shared insertions inherited from a common ancestor
a function lost once and inherited since

Show the answer

One genetic code across all life: descent from a single ancestral population 200,000 matching retrovirus sites: shared insertions inherited from a common ancestor A disabled vitamin C gene: a function lost once and inherited since Human chromosome 2: two ancestral chromosomes fused in one lineage

1.[3p] Why is a shared error better evidence of common ancestry than a shared correct feature?

2.[2p] About what percentage of the human genome consists of endogenous retrovirus sequence?

3.[3p] A critic says retroviruses have preferred insertion sites, so shared positions could be coincidence. What answers this without appealing to probability?

4.[3p] Why is a broken GULO gene stronger evidence than a working one would be?

5.[3p] The descent account predicts that the human and guinea pig GULO pseudogenes carry the same disabling mutations.

6.[3p] Which features must a human chromosome show if it is a fusion of two ancestral ape chromosomes?

7.[2p] Humans have 23 pairs of chromosomes. How many pairs do chimpanzees, gorillas and orangutans have?

8.[2p] What is the six-base sequence repeated at vertebrate telomeres?

9.[3p] Match each genomic observation to what it is evidence of.

1.[3p]
Why is a shared error better evidence of common ancestry than a shared correct feature?

2.[2p]
About what percentage of the human genome consists of endogenous retrovirus sequence?

3.[3p]
A critic says retroviruses have preferred insertion sites, so shared positions could be coincidence. What answers this without appealing to probability?

4.[3p]
Why is a broken GULO gene stronger evidence than a working one would be?

5.[3p]
The descent account predicts that the human and guinea pig GULO pseudogenes carry the same disabling mutations.

6.[3p]
Which features must a human chromosome show if it is a fusion of two ancestral ape chromosomes?

7.[2p]
Humans have 23 pairs of chromosomes. How many pairs do chimpanzees, gorillas and orangutans have?

8.[2p]
What is the six-base sequence repeated at vertebrate telomeres?

9.[3p]
Match each genomic observation to what it is evidence of.