Ch. 27 Flashcards Preview

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Flashcards in Ch. 27 Deck (21):
1

Which of the following is an example of a quantitative trait?
A) height
B) rate of glucose metabolism
C) ability to learn a maze
D) all of the above

D) all of the above

2

Saying that a quantitative trait follows a continuum means that..

Phenotypes are continuous and do not fall into discrete categories

3

For quantitative traits, genotypes and phenotypes tend to overlap because..

- they are polygenic
- environmental variation affects the trait

4

A QTL is a ___ where one or more genes affecting a quantitative trait are ___.

Site in a chromosome, located

5

To map QTLs, strains are crossed that differ with regard to..

A quantitative trait and molecular markers

6

Normal distribution of a quantitative trait.

Is height a discontinuous (discrete) trait or does it follow a continuum?

In most populations (like this one), height follows a continuum

7

What does it mean to say that these alleles are additive?

When alleles are additive, this means they contribute in an incremental way to the outcome of a trait.

Having three heavy alleles will make an individual heavier than having two heavy alleles.

8

Explain how gene number and environmental variation affect the overlaps between phenotypes and different genotypes.

Increases in gene number and more environmental variation tend to cause greater overlaps between different genotypes and the same phenotype.

9

The general strategy for QTL mapping via molecular markers.

What are the two ways that strains A and B differ?

These two strains differ with regard to a quantitative trait and they differ in their molecular markers.

10

___ ___ is the study of traits that can be described numerically.

Quantitative genetics

11

Complex traits-

Usually controlled by more than one gene and are significantly influenced by environmental factors

12

Anatomical traits

Height, weight, number of bristles Drosophila, ear length in corn, and the degree of pigmentation in flowers and skin

13

Physiological traits

Metabolic traits, speed of running and flight, ability to withstand harsh temperatures, and milk production in mammals

14

Behavioral traits

Mating calls, courtship rituals, ability to learn a maze, and the ability to grow or more toward light

15

Diseases

Predisposition toward heart disease, hypertension, cancer, diabetes, and arthritis

16

___ ___ are traits that fall into two or more discrete categories.

Discontinuous traits

17

___ ___ show a continuum of variation within a group of individuals.

Quantitative traits

18

An alternative way to describe them is a ___ ___.

Frequency distribution

19

Often, data fall into a ___ ___.

Normal distribution

20

___ ___ refers to the transmission of traits that are governed by two or more genes.

Polygenic inheritance

21

The locations on chromosomes that affect the outcome of quantitative traits are called ___ ___ ___.

Quantitative trait loci (QTLs)