Test 6 Flashcards

(60 cards)

1
Q

What trait is a result of quantitative genetics?

A

skin color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the Infinitesimal model of genetics?

A

lots of small genes, each with roughly equal effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why does the environment need to be standardized when studying genetic effects?

A

Genes interact with the environment; indeed, the environment is part of the phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What was one of the impact’s when RA Fisher’s Infinitesimal theory was applied?

A

Dairy producers saw a logrithmic increase in milk production per cow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the difference between the population average and the variation in the population for a trait?

A

The variation is the range around the average

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which of the following has a heritability of 0.0?

A

Number of legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which of the following has a heritability of 0?

A

clipped mane of horse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which of the following is genetic and has a heritability of 0?

A

number of legs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which of the following traits is mostly the result of additive genetics?

A

Height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why do heritability studies focus on additive modes of inheritance rather than recessive/dominant and epistasis?

A

Dominant/recessive genetics and epistasis requires a specific set of genes be inherited together and that is less predictive than genes with additive modes of inheritance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the difference between heritability and estimated breeding value (EBV)?

A

Heritability is characteristic of the trait and estimated breeding value is characteristic of the individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Will heritability of a trait be the same in different breeds?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Heritability is standard characteristic of the trait in all members of a species.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why might heritability for a trait decrease over time?

A

Improvement of the breed through selection and Discovery that offspring are performing more poorly than predicted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the period when the Thoroughbred horse is considered to have been founded?

A

1600s-1700s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What aspect of genetics does the sire-line track?

A

Y chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What aspect of genetics does the dam-line track?

A

Mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Approximately what percent of Thoroughbred horses trace their male line back to the Darley Arabian?

A

95%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Approximately what percent of the genes in Thoroughbred horses are descended from the Darley Arabian

A

6.5%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which is an accurate description of the modern Thoroughbred breed?

A

Hybrid of native English horses and horses imported from the Mediterranean region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What was Cunningham’s Paradox?

A

Thoroughbred horses have had limited improvement in race times but the population has lots of variation measured for racing performance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Heritability of race time in Thoroughbred horses is difficult to measure because of which of the following?

A

There is no single trait we can identify as racing. Horses race different distances, at different ages on different surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which of the following two traits resulted in discovery of the best heritability scores for racing?

A

Log of Money earned and handicapping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What was the result of GWAS studies for racing performance in Thoroughbred horses?

A

Lots of areas of interest were identified, but different ones in different studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Evidence was found for MSTN, PDK4 and COX4I2 having an impact on racing performance. Why were those particularly significant?
The evidence was confirmed by cross checking the effects in multiple tests for each one of them, sometimes confirming statistical effect by testing a second population.
26
Bruce Lowe numbers measure....
Prominent dams in a pedigree
27
Dosage measures....
Deep pedigree of sires
28
Nicking measures...
Values of mating
29
Why do heritability values vary between studies?
Different distances measured Different populations Different measures of performance
30
Why might the slope of race-time improvement have declined for Thoroughbred horses?
Top horses reaching a physical limit for performance
31
Handicapping is...
A subjective evaluation of quality Weight added to a saddle to slow a horse down Time Form and Beyer's Numbers
32
What does hemizygous mean?
A normally diploid individual has only one copy of a gene; genes on X in males; genes on X for XO females
33
The X chromosome does not have any genes.
False
34
What is the likely origin of DNA found in mitochondria?
Bacteria that colonized primordial cells
35
What is a function of mitochondria in the cell?
Gernerate energy in the form of ATP
36
Why do we refer to the inheritance of mitochondrial DNA as having "Tail-Female" inheritance?
Mitocondria are almost always inherited from the egg.
37
What is associated with the number of mitochondria in a cell?
Cells with high metabolic activity have more mitochondria than cells with low activity
38
When a research result is statistically significant, what does that mean?
The result is repeatable
39
Which of the following is true about the mitochondria genome?
It is small, having only 16,500 bp compared to 2.5 billion bp on chromosomes
40
What is true about the genes for function of mitochondria?
Most of the genes for mitochondria function are actually on chromosomes
41
Why do we think that mitochondria are descended from primordial prokaryotes (bacteria)?
Their DNA sequence is more similar to that of prokaryotes than than of autosomes. Mitochondria have codons like bacteria and not like vertebrate codons The mitochondria genome is circular like bacteria
42
What is the name of the theory that prokaryotes were the origin of mitocondria?
Endosymbiotic theory
43
Why is the mitochondrial DNA a good tool for a molecular clock?
Mitochondia DNA polymerase is error prone
44
What conclusions followed the comparison of mitochondria haplotypes of horses from around the world?
Many mares were part of the foundation of domestic horses
45
The X and Y chromosome have very clear differences. Why do the X and Y chromosome pair during meiosis?
They share a small set of genes in the pseudo autosomal region
46
Why do we think the Y chromosome evolved from the X chromosome?
When the PAR is longer in some species, the genes found are X chromsosome genes
47
Why do we think a large number of stallions contributed to the foundation of the domestic horse?
We see a large number of Y chromosome haplotypes in ancient DNA
48
Why do we think that most modern horse breeds have a single Y chromosome haplotype?
Breeders choose stallions from the Mediterranean region between 700 and 1200 years ago
49
Where is the microbiome found?
Throughout the body
50
What is the difference between pathogenic bacteria and commensal bacteria?
Commensal bacteria do not cause disease while pathogenic bacteria do.
51
There is more variation between individuals in their microbiome than in their genome.
True
52
What is the ratio of microbiome cells to the genome cells? (Roughly)
3:1; micorbiome cells outnumber animal cells
53
What is the mass (weight) of the microbiome?
About 6 pounds, according to the video. By comparison, the human brain weighs only 3 pounds.
54
The microbiome contributes gene functions and substances not found or produced by the horse or human genome.
True
55
What was the limit on discovery for early investigations (up to 1970) of the microbiome?
Ability to grow the microbes in the laboratory
56
How did DNA sequencing make it possible to advance microbiome studies?
DNA sequences were found that were for microbes we had not been able to culture
57
What was the initial basis for identifying microbes as belonging to species never seem before? Or identifying which species they did belong to?
Sequence of 61s Ribosomal DNA sequence
58
What influences the type of microbe found in a location?
vaginal vs cesarean birth diet Age Genome
59
What are biofilms?
A community of microbes that interact in a commensal fashion
60
What is the most common site for study of the microbiome?
fecal material