Chapter 4: Modern GeneticsChapter 4: Modern GeneticsChapter 4: Modern GeneticsChapter 4: Modern Genetics

ReviewReview

An example of a trait that has

multiple alleles.

blood types

If a person has the combination of alleles O and B what would their blood type be?

B blood type

Skin color and height are traits that show a

large number of different phenotypes

because they are controlled by

_________.

many genes

(polygenic inheritance)

The effects of genes are often changed by

an organism’s ____________.

environment

The body cells contain _____ chromosomes.

46

The sex cells contain ___ chromosomes.

23

The two sex chromosomes

carried by a male are _____.

XY

The two sex chromosomes carried by a female are ____.

XX

Genes carried on the X or Y chromosomes are called _________.

sex-linked genes

An example of a condition that is sex-

linked is ______.

Hemophilia or

color-blindness

Sex-linked traits occur more often in ______, because

they carry only one X

chromosome.

males

A chart that tracks which members of a

family have a particular trait is called a ________.

pedigree

In a pedigree chart a square is a symbol

for a _____.

male

A half-shaded circle on a

pedigree chart would indicate a

_________.

carrier female

An abnormal condition that a person inherits

through genes or chromosomes is

a

__________.

genetic disorder

A genetic disorder in which a

person’s blood clots very slowly

or not at all is called ______.

hemophilia

People with an extra copy of chromosome 21 have a disorder

called _________.

Down syndrome

A person who has difficulty

distinguishing between the colors red and green has the sex-linked trait

called ________.

colorblindness

A picture of all the chromosomes in a

cell is called a _________.

karyotype

Professionals who help couples

understand their chances of having a

child with a particular disorder are called

_________

genetic counselors

A procedure in which fluid from a developing baby is removed to test for genetic disorders is

called ________.

amniocentesis

A genetic disorder in which the body

produces abnormally thick mucus is called

__________.

cystic fibrosis

In _______, breeders cross two

genetically different individuals.

hybridization

A _____ is an organism that is

genetically identical to the organism from which it was produced.

clone

Inserting working copies of a gene directly into cells of a person with a genetic disorder is

referred to as _______.

gene therapy

The process of selecting a few organisms with

desired traits to serve as parents of the next generation is called

_________.

selective breeding

The transfer of genes from one

organism to another is called

________.

genetic engineering

The crossing of two individuals

that have identical or similar sets of alleles is called

_______.

inbreeding