Overview of Human Genetics

Alternative forms of genes are called __________.

Any two matched genes that are __________ are called alleles.

When the two alleles controlling a trait are different, the individual is __________ for the trait.

A person's genetic makeup is referred to as his or her genotype.

The expression of genes is called the __________.

A phenocopy occurs when __________.

The appearance of freckles is considered the __________.

Which of the following processes may separate linked genes during meiosis?

With the exception of gametes, human cells have __________ pairs of chromosomes.

A permanent structural change of a gene is called __________.

Genes that are located on the same chromosome are said to be __________.

A person without a Y chromosome will __________.

The 46 chromosomes of a zygote come from __________.

The number of different gametes that can be produced in a male, based on independent assortment alone, equals __________.

An allele that is able to mask the expression of its partner allele is said to be __________.

Codominant alleles are present in __________.

An organism with five pairs of homologous chromosomes could produce __________ different gametes on the basis of independent assortment alone.

The larger the number of offspring, the greater the likelihood that the observed ratios will conform to the values predicted by the Punnett square.

Many genetic disorders, such as albinism, cystic fibrosis, and Tay-Sachs disease, are inherited as simple recessive traits.

The X and Y sex chromosomes are the best examples of homologous chromosomes.

How many chromosomes are in a normal haploid human cell?

In dominant-recessive inheritance, if an individual is heterozygous, which phenotype will be expressed?

The form of inheritance in which the heterozygous state is expressed as an intermediate is __________.

A person who inherits the A and the O blood type alleles will possess which blood type?

What is the probability that a child will be born with a recessive trait if both parents are heterozygous for the trait?

In the human blood type AB, both alleles are expressed and are therefore __________.

If the allele for brown hair is represented by B, it means that __________.

Heterozygous parents who have had one child with a recessive disease have a __________% chance of having a second child born with the same recessive disease.

Use the following information to solve the problem using a Punnett square: Assume that the dominant B allele encodes brown eyes and the recessive b allele encodes blue eyes. An individual with the genotype bb has children with an individual of the genotype Bb. What is the percent chance that they would have children with blue eyes?

Which of the following disorders is NOT inherited as a simple recessive trait?

Linked genes are __________.

Red-green color blindness exhibits __________ inheritance.

X-linked recessive traits are expressed more frequently in males because __________.

Extrachromosomal inheritance involves genes passed on by the mother’s __________.

If a male inherits a sex-linked gene for color blindness, __________.

Traits that display continuous phenotypic variation are usually determined by which form of inheritance?

Most human traits are determined by __________.

In females, one of the X chromosomes is inactivated by __________.

Which of the following is NOT one of the three basic levels of gene control?

Amniocentesis and chorionic villus sampling are both examples of a category of genetic screening called __________.

The most common form of fetal testing is __________.

A karyotype is a complete __________.

Heterozygous individuals that can pass on recessive, abnormal conditions even if they do NOT express the disease are referred to as __________.

A type of treatment useful in correcting single-gene disorders is __________.