Question 1

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

Accepted Answer

At the transmission level, one sees "stepwise" distributions in discontinuous inheritance, but "smoother" or more bell -shaped distributions in continuous inheritance, as shown in the following figures:

Question 2

Bell -shaped distributions produced by plotting results of F2 and F3 crosses are typical of which type of inheritance?
A) alternation of generations
B) multiple -factor inheritance
C) codominance
D) hemizygosity
E) incomplete dominance

Accepted Answer

Bell-shaped distributions, also known as normal distributions, are typical of multiple-factor inheritance, where multiple genes contribute to a trait, resulting in a continuous range of phenotypes.

Question 3

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

three

Question 4

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

Accepted Answer

The answer of Given the following numbers, calculate the mean:...

Question 5

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

Accepted Answer

The answer of How many gene pairs are involved in...

Question 6

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

Accepted Answer

The answer of Which formula can be used to determine...

Question 7

Environmental factors typically influence inheritance of
A) codominance
B) dominantly inherited traits
C) polygenic traits
D) trihybrid crosses
E) multiple alleles

Accepted Answer

Polygenic traits are influenced by multiple genes and can be affected by environmental factors, leading to a range of phenotypes.

Question 8

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 9

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 10

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 11

Quantitative inheritance involves the interaction of a number of gene loci. The pattern of
Genetic transmission typical of quantitative inheritance is
A) a 9:3:3:1 ratio
B) typical of Mendelian inheritance
C) continuous variation of phenotypic expression
D) discontinuous distributions such as 3:1 ________.
E) usually a pattern that clearly reflects dominance and recessiveness

Accepted Answer

Quantitative inheritance results in continuous variation of phenotypic expression due to the additive effect of multiple genes, unlike Mendelian inheritance which shows distinct ratios.

Question 12

If the proportion of F2 individuals resembling either of the two most extreme parental phenotypes can be determined, which 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 13

What are the name and formula for describing sample variability?

Accepted Answer

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

Question 14

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 15

Assume that a cross is made between tall and dwarf tobacco plants. The F1 generation showed intermediate height, whereas 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?
A) codominance
B) incomplete dominance
C) hemizygosity
D) multiple -factor inheritance
E) alternation of generations

Accepted Answer

The distribution of heights in the F2 generation suggests polygenic inheritance, where multiple genes contribute to the trait, resulting in a range of phenotypes.

Question 16

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 17

Characteristics exhibited by continuously varying traits include _.
A) 3:1 and 1:1 ratios
B) sex -linked genes only
C) a 9:3:3:1 ratio
D) autosomal genes only
E) quantification by measuring, weighing, counting, etc.

Accepted Answer

Continuously varying traits are typically quantitative traits that can be measured, weighed, or counted, such as height or weight, rather than fitting into simple Mendelian ratios.

Question 18

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

Accepted Answer

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

Question 19

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 20

Some traits are polygenic but do not show typical continuous distributions. For example, type II diabetes is determined by a number of genes, but one is either
diagnosed as diabetic or not diabetic based on blood sugar levels. How might one explain such a phenomenon?

Accepted Answer

The answer of Some traits are polygenic but do not...

Quiz 21: Quantitative Genetics and Multifactorial Traits

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

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

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?

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

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

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

Environmental factors typically influence inheritance of

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

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 _.

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?

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

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

What are the name and formula for describing sample variability?

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

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?

Characteristics exhibited by continuously varying traits include _.

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

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

Some traits are polygenic but do not show typical continuous distributions. For example, type II diabetes is determined by a number of genes, but one is either diagnosed as diabetic or not diabetic based on blood sugar levels. How might one explain such a phenomenon?