Download Genetic Disorders

Genetic Disorders
Caused by ___?________ in the DNA
mutations
Recessive Disorders
• Cause of most genetic disorders
• 2 recessive alleles: 1 from mom and 1 from dad
Autosomal Recessive Disorders
Example: Sickle Cell Anemia
• Most common blood disorder
• Usually affects those of African decent
– Deformed “sickled” red blood cells
– What problem will that cause? What do blood
cells carry?
Ryan Clark
https://www.youtube.com/watch?v=K
hLdthi89mU
Example: Sickle Cell Anemia
• Most common blood disorder
• Usually affects those of African decent
– Deformed “sickled” red blood cells
– What are some problems that could stem from
this?
Practice-autosomal recessive
• Show the results of a cross between two individuals
heterozygous for Sickle Cell Disease.
• (S-normal s-disease)
• What is the percent chance that the offspring will
have sickle cell?
Example
If both parents are heterozygous (Ss)…….
Practice-autosomal recessive
• Show the results of a cross between one
heterozygous and one individual who has Sickle Cell
Disease. (S-normal s-disease)
• What is the percent chance that the offspring will
have sickle cell?
Autosomal Recessive Disorders
• Cystic Fibrosis
• Abnormal transport o of chloride and sodium
= thick mucus secretions = terrible cough
• Most common in Caucasians of European
decent
Autosomal Dominant
• Autosome: all body cells (not sex cells)
• Dominant: strong allele/big letters
• Must inherit 1 dominant allele: 1 from
mom or 1 from dad to end up with the
genetic disorders
Autosomal Dominant
• Huntington’s Disease
– Damages nerve cells
• Marfran Syndrome
– Mutation causes a problem with the connective
tissue in the body
Practice-autosomal dominant
• Show the results of a cross between two individuals
heterozygous for Huntington’s Disease. (H-disease, h-normal)
• What is the percent chance that the offspring will
have Huntington’s Disease?
Sex-linked traits
Female XX
Male XY
Sex Determination
• X chromosome carries genes (longer chromosome)
• Y does NOT carry many genes (shorter chromosome)
• Females get 2 X chromosomes so they have a
50%/50% of getting the disorder
• Males get 1 X chromosome from mom so if the
chromosome is present on that X then the child
has the disorder
http://dnalc.org/view/16263Animation-10-Chromosomes-carrygenes-.html
Sex Linked traits-Colorblind
• The gene for colorblindness is carried on the
X-chromosome.
• C- normal; c-colorblind
• Mother: XCXc
• Father: XcY
Sex Determination Questions
1. How is sex linked inheritance
from autosomal inheritance?
2. Why are more males colorblind
than females?
Genetic Disorders Packet
#1-10 completed
by Thursday 3/19