Chapter 7
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Chapter 7. Non- Mendelian Genetics. 4 Types of Non - Mendelian Genetics. Incomplete Dominance Codominance Multiple Alleles Sex-linked Inheritance. Incomplete Dominance. Traits are inherited with no definite dominance of either allele. Phenotypes combine to create a separate trait.

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Chapter 7

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Chapter 7

Chapter 7

Non-Mendelian Genetics


4 types of non mendelian genetics

4 Types of Non-Mendelian Genetics

Incomplete Dominance

Codominance

Multiple Alleles

Sex-linked Inheritance


Incomplete dominance

Incomplete Dominance

  • Traits are inherited with no definite dominance of either allele.

  • Phenotypes combine to create a separate trait.

  • Example, red and white snapdragons offspring pink snapdragons


Punnett square of incomplete dominance cross

Punnett Square of Incomplete Dominance Cross

  • Expressed as R and r alleles as a Punnett Square Cross.

  • RR (red) X rr

    (white)


Codominance

Codominance

  • Expression of both alleles equally

  • Phenotype of both traits are seen in heterozygous individuals

  • Example black rooster and white chicken produce offspring with black and white feathers.


Punnett square of codominant cross

Punnett Square of CodominantCross

  • Expressed as two separate traits in a Punnett Square Cross

  • BB (black) X WW (white)


Multiple alleles

Multiple Alleles

  • More than two alleles of a certain trait are present

  • Example ABO blood types

  • IA and IB and i alleles determine blood types in Punnett Square.


Punnett square of multiple alleles cross

Punnett Square of Multiple Alleles Cross

IA i X IB i

Both parents are heterozygous for blood type


Sex linked trait

Sex-linked trait

  • Gene on the X or Y chromosome

  • Males only have one copy of X, Females have two copies.

  • Females can be heterozygous for the trait.

  • Example Red-Green colorblindness


Inheritance pattern for red green colorblindness

Inheritance pattern for red-green colorblindness

XX (heterozygous carrier)

XY (normal color sight)


Inheritance pattern for red green colorblindness1

Inheritance pattern for red-green colorblindness

XX (heterozygous carrier)

XY (colorblind male)


What is a pedigree chart

What is a Pedigree Chart?

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

  • Scientists or a genetic counselor would find out about your family history and make this chart to analyze.


What does a pedigree chart look like

What does a pedigree chart look like?


Notation on the pedigree

Notation on the Pedigree

  • A circle represents a female.

  • A square represents a male.

  • A completely shaded square or circle indicates the person has the trait.

  • A not shaded shape indicates that a person neither has the trait nor is a carrier.

  • A half-shaded shape indicates that a person is a carrier.


Chapter 7

Most common signs and symbols used in pedigree analysis


Interpreting a pedigree chart

Interpreting a Pedigree Chart

  • Determine if the pedigree chart shows an autosomal or X-linked disease.

    • If most of the males in the pedigree are affected the disorder is X-linked

    • If it is a 50/50 ratio between men and women the disorder is autosomal.


Example of pedigree charts

Example of Pedigree Charts

  • Is it Autosomal or X-linked?

Autosomal


Interpreting a pedigree chart1

Interpreting a Pedigree Chart

  • Determine whether the disorder is dominant or recessive.

    • If the disorder is dominant, one of the parents must have the disorder.

    • If the disorder is recessive, neither parent has to have the disorder because they can be heterozygous.


Example of pedigree charts1

Example of Pedigree Charts

  • Dominant or Recessive?

  • Dominant


Example of pedigree charts2

Example of Pedigree Charts

  • Dominant or Recessive?

  • Recessive


Summary

Summary

  • Pedigrees are family trees that explain your genetic history.

  • Pedigrees are used to find out the probability of a child having a disorder in a particular family.

  • To begin to interpret a pedigree, determine if the disease or condition is autosomal or X-linked and dominant or recessive.


Queen victoria s family and hemophilia

Queen Victoria’s Family and Hemophilia


Chapter 7

  • karyotype

  • picture of the chromosomes in a cell used to check for abnormalities


Chapter 7

A Human Karyotype has photos of all the matched pairs of human chromosomes from one cell, stained to show banding patterns, and arranged from long to short, with centromeres near the top.Here are our numbers 6-9…


Chapter 7

Kleinfelter syndrome


Chapter 7

Turner syndrome


Mutations

Mutations

  • A mutation is any change in the DNA sequence.

  • Gene mutations or chromosomal mutations

  • Mutations in gametes may be passed on to offspring

  • Mutations in somatic cells cannot be passed to offspring


Types of gene mutations

Types of Gene Mutations

  • Point mutation a change in a single base pair in the DNA.

    THE DOG BIT THE CAT

    THE DOG BIT THE CAR


Types of gene mutations1

Types of Gene Mutations

  • Frameshiftmutation a single base pair is added or deleted, causing a shift in how the DNA strand will be read.

    THE DOG BIT THE CAT

    THE DOB ITT HEC AT


Chromosome mutations

Chromosome Mutations

  • Deletion-part of a chromosome is left out.

  • Insertion-part of a chromatid breaks off & attaches to its sister chromatid.


Chromosome mutations1

Chromosome Mutations

  • Inversion-part of a chromosome breaks off & reinserts backwards.

  • Translocation-part of one chromosome breaks off & is added to a different chromosome.


What causes mutations

What causes mutations?

  • spontaneous mistakes

  • environment

    Mutagen - any agent that can cause a change in DNA is called a. (x-rays, UV light, asbestos)


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