Pedigrees

Pedigrees

A pedigree is a chart of the genetic history of family over several generations.

Vocabulary

• Genotype is the genetic make up of an organism (Tt)

• Phenotype is the physical/ observable trait (tall)

• Dominate allele-Phenotipaclly expressed over other allele

• Recessive allele- only express in absence of dominate allele

Multiple Choice

. An organism’s physical appearance is its

• Genotype

• Phenotype

• codominance

Multiple Choice

An organism’s genotype is its

• Physical appearance

• Feather color

• Genetic makeup

Multiple Choice

How does a geneticist use pedigrees?

• to replicate identical strings of DNA

• to trace the inheritance of traits over generations of families

• to create genetic crosses

Multiple Choice

What does the notation TT mean to geneticists?

• two dominant alleles

• two recessive alleles

• one dominant and one recessive allelle

Autosomal traits

all the other genes in the body that are not sex-linked.

Sex-linked Trait

Traits controlled by genes located on sex chromosomes. Also known as X-linked trait. X-link traits are most likely recessive.

Poll

Why are sex-linked traits more common in males than in females?

• All alleles on the X chromosome are dominant.

• All alleles on the Ychromosome are dominant.

• A recessive allele on the X chromosome will always produce the trait in a male

Multiple Choice

Sex-linked genes are genes on

• the Y chromosome only.

• the X chromosome only

• the X and Y chromosomes.

Purpose of Pedigree charts

to trace the inheritance of traits over generations of families

Poll

What is the purpose of a Pedigree?

• to create genetic crosses

• to trace the inheritance of traits over generations of families

Pedigree symbols

• Circles represent females

• Squares represent male

• Carriers of traits will be half shaded

• Horizontal line between male and femail mean marriage

• Vertical lines show offspring

• Shaded in fully mean trait is shown.

Pedigree symbols

• Rows are expressed by generations

• Those who marry into the family are placed in sequincial order

• Spoke as Generation I,II,III,IV,V,VI (roman numberals

• Person by placement in row.

• Written as II-1 or I-2. Spoke Generation 2 person 1 or generation 1 person 2

• Shaded in fully mean trait is shown.

Multiple Choice

A carrier is a person who has

• one recessive and one dominant allele for a trait.

• two dominant alleles for a trait.

• two dominant alleles for a trait.

Poll

In which generation are the parents purebred?

• F1

• F2

Poll

In which generation are they hybrids?

• F!

• F2

Multiple Choice

What do the circles in the pedigree represent?

• carrier

• male

• Heterozygous

• female

Multiple Choice

What do the squares represent?

• carrier

• male

• Heterozygous

• female

Multiple Select

Which pairs of individuals have children?

• AB,

• CD

• FG

• HI

• MN

Multiple Select

Which individuals have the trait that is traced by the pedigree?

• I-2 Generation1 person 2

• III-1, Generation 3 person 1

• II-4 Generation 2 person r

• III-3 Generation 3 person 3

Multiple Select

Which individuals are carriers of the trait that is traced by the pedigree?

• I-1 Generation1 person

• III-6, Generation 3 person 6

• II-4 Generation 2 person r

• II-1 Generation 2 person 1

• III-5 generation 3 person 5