patterns of heredity & human genetics
DESCRIPTION
Patterns of Heredity & Human Genetics. What is a pedigree?. Is a graphic representation of genetic inheritance. Pedigree Info. Shows genetic relationships within a family Square=male, circle female Horizontal line=reproduction Vertical line=connects parents to offspring. - PowerPoint PPT PresentationTRANSCRIPT
Patterns of Heredity & Human Genetics
What is a pedigree?
Is a graphic representation of genetic inheritance.
Pedigree Info
• Shows genetic relationships Shows genetic relationships within a familywithin a family
• Square=male, circle femaleSquare=male, circle female• Horizontal line=reproductionHorizontal line=reproduction• Vertical line=connects Vertical line=connects
parents to offspringparents to offspring
Pedigree Chart for colorblindness
What is a karyotype?
• Shows picture of chromosomes Shows picture of chromosomes arranged in pairsarranged in pairs
• Contains SEX CHROMOSOMES (X and Contains SEX CHROMOSOMES (X and Y) and the rest (called AUTOSOMES)Y) and the rest (called AUTOSOMES)
What are some recessive heredity disorders and traits?
CYSTIC FIBROSISCYSTIC FIBROSIS
•Caused by RECESSIVE allelesCaused by RECESSIVE alleles•Excessive mucus in lungsExcessive mucus in lungs•Increased susceptibility to Increased susceptibility to infectioninfection
Other DisordersOther Disorders
Tay-Sachs Disease Recessive disorder
of the central nervous system
An enzyme is missing that breaks down a lipid produced and stored in the nervous system.
Phenylketonuria (PKU)
Recessive disorder that results from a missing enzyme that converts amino acid phenylalanine into tyrosine.
It damages the nervous system and to the brain.
One of the few we can prevent by knowing the baby is a carrier.
What are some dominant heredity disorders and traits?
Tongue RollingTongue Rolling
Widow’s PeakWidow’s Peak
Attached EarlobesAttached Earlobes
Hitchhiker ThumbHitchhiker Thumb
Chin FissureChin Fissure
FrecklesFreckles
PolydactylPolydactyl
http://www.ktvu.com/news/18608582/detail.html#-
DimplesDimples
What is Genetics?What is Genetics?•The study of traits being passed The study of traits being passed from generation to generation.from generation to generation.
What is Codominance?What is Codominance?•When both alleles are expressed fully in When both alleles are expressed fully in phenotype phenotype
What is Incomplete What is Incomplete Dominance?Dominance?
•Alleles blend together, neither being Alleles blend together, neither being dominant dominant
Incomplete DominanceIncomplete Dominance
What are Multiple Alleles?What are Multiple Alleles?•More than two types of alleles for a traitMore than two types of alleles for a trait
Blood TypeBlood Type
Blood TypeBlood Type
•3 Alleles for antigens = 3 Alleles for antigens = IIAA, , IIBB, , and and ii
•IIAA and and IIB B are codominant, are codominant, ii is is recessiverecessive
What are Polygenic Traits?What are Polygenic Traits?•Many genes control traitsMany genes control traits
•Examples: height, skin colorExamples: height, skin color
What are Sex-linked Genes?What are Sex-linked Genes?•Genes located on the sex Genes located on the sex chromosomes, many on the “X”chromosomes, many on the “X”
Sex-linked TraitsSex-linked Traits•COLORBLINDNESSCOLORBLINDNESS
•Location = X chromosomeLocation = X chromosome
•Inability to distinguish different Inability to distinguish different colors, usually reds and greenscolors, usually reds and greens
Sex-linked TraitsSex-linked Traits
Sex-linked TraitsSex-linked Traits
Sex-linked TraitsSex-linked Traits•Why are males more likely to have Why are males more likely to have sex-linked traits?sex-linked traits?
•Colorblindness in males, 1 in 10, 1 Colorblindness in males, 1 in 10, 1 in 100 femalesin 100 females
•Males only have one X, so only Males only have one X, so only one recessive allele necessaryone recessive allele necessary
•Females, 2 X’s, so two recessives Females, 2 X’s, so two recessives necessary necessary