tay-sachs disease
DESCRIPTION
GENETIC DISORDERS. MIGUEL URBINO & JAZZ RANDALL PERIOD 3. TAY-SACHS DISEASE. PLEASE KEEP IN MIND. OTHER PEOPLE MAY Have THIS DISEASE AND BE RESPECTFUL WHEN REACTING . SUMMARY. Very rare This disorder is inherited It destroys the nerve cells in your brain and spinal cord - PowerPoint PPT PresentationTRANSCRIPT
TAY-SACHS DISEASEGENETIC DISORDERS
MIGUEL URBINO & JAZZ RANDALLPERIOD 3
OTHER PEOPLE MAY HAVE THIS DISEASE AND BE RESPECTFUL WHEN REACTING
PLEASE KEEP IN MIND
SUMMARY• Very rare• This disorder is inherited• It destroys the nerve cells in your brain and
spinal cord• Recessive gene • Mostly occurs in infants• Survival rate is up to 3 to 4 years of age
INFANTS
• Lose their motor skill ability such as turning over, sitting, and crawling
• Exaggerated startled reactions to loud noises • Not easily noticed at first• Go through seizures, vision and hearing loss,
intellectual disability, and paralysis
CHROMOSOME 15
The HEXA- Chromosome 15Tay Sachs is caused by mutations in the HEXA gene
MODE OF INHERITANCE How would one acquire Tay Sachs? -if the parents of an offspring are both a carrier of the disease then
you get full Tay Sachs What does sex linked/x-linked, autosomal recessive or autosomal
dominant mean? - If a disease is autosomal dominant, it means you only need to get the gene
from one parent in order for you to inherit the disease. - An autosomal recessive disorder means two copies of the gene must be
shown in order for you to inherit the disease or trait. - Sex-linked means that a single gene on the X chromosome can cause the
disease. This can happen in boys and girls but in the case of males they may not survive.
ALLELES• An allele is an alternative form of a gene that is located at a specific
position on a specific chromosome• 2/per gene• They come from our parents whether they carry the trait or not• Recessive= r Dominate= R• Dominant means you are more likely to inherit something from your
parents• Recessive means you can inherit it from your parents but it is a less
likelihood you will
PUNNETT SQUARESFATHER'S GENES
T t
MOTHER'S T TT Tt
GENES t Tt tt
FATHER'S GENES
T T
MOTHER'S T TT TT
GENES t Tt Tt
FATHER'S GENES
T T
MOTHER'S T TT TT
GENES T TT TT
FATHER'S GENES
t t
MOTHER'S T Tt Tt
GENES t tt tt
Ratios: 1 : 2 : 11TT : 2Tt : 1t
FATHER'S GENES
T t
MOTHER'S T TT Tt
GENES t Tt tt
ANALYZING PUNNETT SQUARES
Percentages: 25% : 50% : 25%
25%TT : 50%Tt : 25%t
ANALYZING PUNNETT SQUARES (CONTINUED)
What do the letters mean?FATHER'S GENES
T t
MOTHER'S T TT Tt
GENES t Tt ttPhenotype: (Physical Color)TT= RedTt = Yellowtt = Green
Genotype:TT = Homozygous DominantTt = Heterozygous Dominant
tt = homozygous recessive
ANALYZING PUNNETT SQUARES (CONTINUED)
Genotype and PhenotypeFATHER'S GENES
T t
MOTHER'S T TT Tt
GENES t Tt tt
Phenotype: (Physical Color)Ratios- 1 Red : 2 Yellow : 1 GreenPercentages- 25% Red : 50% Yellow : 25% Green
Genotype:Ratios- 1 TT : 2 Tt : 1 tt
Percentages- 25% TT : 50% Tt : 25% tt
PHENOTYPE:Ratio-Percentages-
FATHER'S GENES
t T
MOTHER'S t
GENES T
PRACTICE PUNNETT PROBLEMS
GENOTYPE:Ratio- Percentages-
3 GENERATIONHYPOTHETICAL PEDIGREE
LEGEND:• Square = Male• Circle = Female• Red = TT• Yellow = Tt• Green = tt
PEDIGREE PRACTICELEGEND:• Square =• Circle =• Shaded =• Half Shaded = • Not Shaded =
ANALYZING PEDIGREES Read the Questions CAREFULLY
1. Is it possible for a TT and Tt to have a tt off-spring?2. Is it possible for a Tt and Tt to have a TT off-spring?3. Is it possible for a tt and TT to have a TT off-spring?
THANK YOU FOR YOURATTENTION AND COOPERATION MIGUEL URBINO & JAZZ RANDALLPERIOD 3