Chapter 7

Chapter 7 Non-Mendelian Inheritance

Carriers

2 copies of autosomal recessive alleles are required for the trait to show up.

1 copy of an autosomal Dominant allele is required for someone to show the trait.

However, someone who does not have the trait/disorder but carries the recessive allele is known as carrier as they can pass the trait down.

Multiple Choice

A person who is a carrier differs from a person who has a genetic disorder. A carrier does / does not show symptoms of a disorder but can / cannot pass the disorder to offspring.

• does/can

• does not/cannot

• does not/can

Sex-linked Traits

A sex-linked trait is a trait that is affected by the sex chromosomes.

Males and females express sex-linked traits differently.

Females have 2 X chromosomes so they can be carriers for recessive traits, and must have 2 recessive chromosomes to show a recessive trait

Males, however, have only 1 X chromosome so they can either show the trait or not show the trait. They can also only pass the trait to daughters as their sons must receive the Y chromosome from them

Multiple Choice

Sex chromosomes determine an organism’s

• Sex-linked traits

• Autosomal traits

• Pedigree

Multiple Choice

All other chromosomes, which do not directly affect an organism’s sex, are called

• Sex-linked

• Autosomal

• Pedigree

Multiple Choice

Sex -linked traits are located on the

• X- chromosomes

• Autosomal chromosomes

X chromosome inactivation

The process by which one of the two X

chromosomes in every cell in female mammals gets turned off.

Even though only one of the two alleles is expressed in each cell, overall, both alleles for each gene on the X chromosomes affect a female’s phenotype.

Multiple Choice

In humans, a gamete from a male determines the sex of the offspring, because a male can pass on

• only X chromosome

• X or Y chromosome

• only Y chromosome

Multiple Choice

A female passes on

• only X chromosome

• X or Y chromosome

• only Y chromosome

Multiple Choice

With X chromosome inactivation, which occurs in males / females, one of the two X chromosomes in every cell is randomly “turned off” / “turned up.”

• males/turned off

• females/turned off

• females/turned up

Multiple Choice

Incomplete dominance is when

• Heterozygous phenotype contains the separate products of both alleles.

• Neither allele is expressed.

• Heterozygous phenotype is somewhere between the homozygous phenotypes.

Incomplete Dominance

This is when the heterozygous phenotype is somewhere in between the homozygous phenotypes. The way described in class is you have a red and white flower and it creates a pink flower.

Multiple Choice

Which of these shows incomplete dominance

• speckled chicken

• albino llamas

• red and yellow flower making an orange flower

Multiple Choice

co-dominance is when

• neither allele is expressed.

• Neither allele neither is dominant or recessive.

• Heterozygous phenotype is somewhere between the homozygous phenotypes.

Co-dominance

Both alleles of a gene are expressed completely, and neither is dominant or recessive. This can be described as you have a red flower and a white flower, you get a speckled red and white flower.

Multiple Choice

Which of these shows co-dominance

• speckled chicken

• albino llamas

• red and yellow flower making an orange flower

Multiple Choice

Which of these shows co-dominance

• A blood

• O blood

• AB blood

Polygenic traits

These are traits that are produced by two or more alleles.

Multiple Select

Which of these requires polygenic traits to be expressed

• eye color

• skin color

• none of these

Epistatic traits

These are genes that affect the expression of other traits.

Multiple Choice

Which of these shows epistatic traits

• AB blood-type

• albino llamas

• red and yellow flower making an orange flower

Multiple Choice

Linked genes are on the

• same chromosome

• different chromosome

• no chromosome

Linkage maps

Show the relative locations of genes on a chromosome. These locations can be used to predict the probability that genes will cross over.

Multiple Choice

Gene linkage describes genes that are on the same chromosome and tend to be inherited

• together

• separately

• not at all

Multiple Choice

Homologous genes can be exchanged through what process during

meiosis.

• telophase

• cytokinesis

• crossing over

Multiple Choice

How are cross-over frequencies related to linkage maps?

• The percentage of cross-overs is added to the map linkages.

• The percentage of cross-overs is converted into map units.

• The percentage of cross-overs is subtracted from the percentage of linkages.

Multiple Choice

which of these genes are more likely to be separated from each other

• d and c

• d and b

• b and c

Multiple Choice

which of these genes are more likely to be inherited togetherfrom each other

• d and c

• d and b

• b and c

How are humans similar to fruit flies?

Human genetics follow the same patterns of heredity. The process of meiosis happens the same way in humans as in fruit flies.

Multiple Choice

Both males and females with a recessive disorder-causing allele can be carriers of a(n) ________________ disorder and pass on the disorder to

their offspring.

• autosomal

• sex-linked

Pedigree charts

can help trace the phenotypes and genotypes in a family to determine the chance that a child might have a certain genetic

disorder.

Multiple Choice

A pedigree is a chart that traces _________________ in a family.

• Phenotype and Genotypes

• phenotypes

• Genotypes

Multiple Choice

how many generations are found in this pedigree

• 1

• 3

• 4

Karyotype

A picture of all of the chromosomes

in a cell. Chemicals are used to stain the chromosomes. The stains produce a pattern of bands on the chromosomes.

Karyotypes can also show if

there are extra chromosomes or missing parts of chromosomes.

Multiple Choice

what does this karyotype show?

• the deletion of a chromosome

• an extra chromosome

• nothing it is perfectly fine