Question 1

How many gene pairs are involved in generating a typical 1:4:6:4:1 ratio?

Accepted Answer

two

Question 2

Given the following numbers,calculate the mean: 10,12,14,16,18.

Accepted Answer

14

Question 3

What formula can be used to determine the number of categories (phenotypes)possible in the F₂ results of a polygenic system?

Accepted Answer

2n + 1 (where n is the number of gene pairs)

Question 4

The 9:3:3:1 ratio is typical of a dihybrid cross in which complete dominance and independent assortment occur.What is the dihybrid ratio with independent assortment of polygenes?

Accepted Answer

The answer of The 9:3:3:1 ratio is typical of a...

Question 5

What is the term given to a random subset of individuals who are selected for measurement in a particular study?

Accepted Answer

The answer of What is the term given to a...

Question 6

Provide a brief description of discontinuous inheritance and continuous inheritance.How are the two related? How are they different?

Accepted Answer

The answer of Provide a brief description of discontinuous inheritance...

Question 7

Assume that you are studying a trait determined by a number of polygenes.If there are seven phenotypic categories,how many genes are probably involved?

Accepted Answer

The answer of Assume that you are studying a trait...

Question 8

List at least three statistical values often used to represent a sample.

Accepted Answer

The answer of List at least three statistical values often...

Question 9

Continuous inheritance is often related to the term quantitative inheritance.Why?

Accepted Answer

The answer of Continuous inheritance is often related to the...

Question 10

What are the name and formula for describing sample variability?

Accepted Answer

The answer of What are the name and formula for...

Question 11

Characteristics exhibited by continuously varying traits include ________.

Accepted Answer

Continuously varying traits can be measured, weighed, or counted rather than easily sorted into distinct categories like those controlled by Mendelian genetics.

Question 12

Assume that four polygenic gene pairs are involved in determining phenotypes of F₂.How many phenotypic classes are expected?

Accepted Answer

The answer of Assume that four polygenic gene pairs are...

Question 13

If the proportion of F₂ individuals resembling either of the two most extreme phenotypes (the parental phenotypes)can be determined,what formula can be applied to determine the number of gene pairs involved?

Accepted Answer

The answer of If the proportion of F₂ individuals resembling...

Question 14

Bell-shaped distributions produced by plotting results of F₂ and F₃ crosses are typical of which type of inheritance?

Accepted Answer

Multiple-factor inheritance, also known as polygenic inheritance, involves the interaction of multiple genes to produce a trait, often resulting in a continuous range of phenotypes that can be represented by a bell-shaped curve when plotted.

Question 15

Assume that a cross is made between tall and dwarf tobacco plants.The F₁ generation showed intermediate height,while the F₂ generation showed a distribution of height ranging from tall to dwarf,like the original parents,and many heights between the extremes.These data are consistent with which one of the following modes of inheritance?

Accepted Answer

The distribution of height in the F₂ generation ranging from tall to dwarf with many heights in between suggests the involvement of multiple genes affecting the trait, which is characteristic of multiple-factor inheritance (also known as polygenic inheritance). This mode of inheritance involves several genes, each contributing a small amount to the phenotype, resulting in a continuous range of phenotypes.

Question 16

In the early part of the twentieth century,Nilsson-Ehle and others described experiments showing that multiple loci may be involved in the inheritance of certain traits.Such patterns are often called ________.

Accepted Answer

The answer of In the early part of the twentieth...

Question 17

When a trait is polygenic,but distinguished from continuous and meristic traits by having a small number of discrete classes,it is said to be a(n)________ trait.

Accepted Answer

The answer of When a trait is polygenic,but distinguished from...

Question 18

Environmental factors typically influence inheritance of ________.

Accepted Answer

Polygenic traits, such as height or skin color, are influenced by multiple genes and environmental factors. The expression of these traits can vary based on environmental factors such as diet, sunlight exposure, or pollution levels.

Question 19

Assume that in the F₂ of a series of crosses,1/64 of the offspring resemble one of the parents (P).How many gene pairs are involved in producing these results?

Accepted Answer

The answer of Assume that in the F₂ of a...

Question 20

Quantitative inheritance involves the interaction of a number of gene loci.The pattern of genetic transmission typical of quantitative inheritance is ________.

Accepted Answer

Quantitative inheritance involves the interaction of multiple gene loci where each locus contributes a small additive effect towards the phenotype, resulting in a continuous distribution of phenotypic expression. This is in contrast to Mendelian inheritance, which involves distinct and predictable ratios of offspring with specific traits based on the dominant and recessive inheritance of single gene loci.

Quiz 23: Quantitative Genetics and Multifactorial Traits