Name: _____________________________ Date: _______________ Period: _________________

Notes: Gene Linkage, Polyploidy and Basic Patterns of Human Inheritance

Genetic Recombination: ● Remember ________________ ________________ is the exchange of genes between homologous

chromosomes during _______________ of meiosis.

● The new combination of genes produced by crossing over and independent assortment is called

______________________ _____________________.

Gene Linkage:● Gregor Mendel’s ___________________________________ states that when two or more traits are

inherited, individual traits are transmitted _____________________ of one another, giving different

traits an equal opportunity of occurring together.

● The _____________of genes on a chromosome results in an exception to Mendel’s law of independent

assortment because linked genes usually do not segregate___________________.

● _______________ ____________ occurs more frequently between genes that are _______ apart than

those that are ___________ together.

● A drawing called a _________________

_____________ shows the sequence of genes on a

chromosome and can be created by using crossover

data.

Polyploidy:● ______________ is the occurrence of having more than ______ paired

(homologous) sets of ___________________. Most eukaryotes are

______________, meaning they have two sets of chromosomes—one set

inherited from each parent.

● A _____________________ organism, for instance, would be designated

3n, which means that is has __________ sets of chromosomes.

○ Examples: ______________________ and __________________

Recessive Genetic Disorders in Humans● A recessive trait is expressed when the individual is _______________ _________________ (____) for

the trait.

● Therefore, those with at least one ________________ (___) allele will not express the

______________ (___) trait.

● An individual who is _________________ (____) for a recessive disorder is called a ______________.

Cystic Fibrosis

● Cystic fibrosis is a progressive, genetic disease that causes persistent _______ infections and limits the ability to_________ over time.

○ It affects the _____________ producing glands, digestive enzymes, and sweat glands.

○ Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in

the sweat.

○ Without sufficient chloride ions in the cells, a thick _______________is secreted.

Albinism● Caused by altered genes, resulting in the absence of the skin pigment ______________ in _________

and ___________.

○

○

○

Tay-Sachs Disease● Tay-Sachs is a rare inherited disorder that progressively destroys ____________ cells (___________)

in the brain and spinal cord.

○ Caused by the absence of the _______________ responsible for breaking down fatty acids

called _____________________.

○ Gangliosides accumulate in the brain, __________________ brain nerve cells and causing

______________ ______________________.

Galactosemia● Recessive genetic disorder characterized by the inability of the body to digest the sugar ___________.

○ During digestion, an enzyme (GALT) breaks down lactose from __________ into galactose and

glucose.

○ Persons with galactosemia lack or have defective GALT and should avoid ________ ________.

Dominant Genetic Disorders in Humans● ________________ _____________ is a fatal genetic disorder that causes the progressive breakdown

of nerve cells in the brain.

● ________________________ (a form of dwarfism) is a genetic condition that causes small body size

and limbs that are comparatively short.

Pedigrees

● A ________________ is a diagram that traces the _________________of a particular trait through

several generations.

Inferring Genotypes and Predicting● Inferring Genotypes

○ Knowing _______________ ____________ can determine what genes an individual is most

likely to have.

● Predicting Disorders

○ Record keeping helps scientists use _____________ ____________ to study inheritance

patterns, determine _____________, and determine ____________________.