sex linked and codominant genes
Post on 07-Jan-2016
27 Views
Preview:
DESCRIPTION
TRANSCRIPT
Sex Linked and Codominant Sex Linked and Codominant Genes.Genes.
Attached Earlobe Unattached Earlobe
Tongue Roll Tongue Flip Tongue Fold Hitchhiker’s Thumb
Ear WaxEar Diagram
Hand Fold
Bent Pinky PTC Tasting Widow’s PeakDimples
Mid-digital hair Bent LittleFinger
Short Hallux Finger Length
carriercarrier
??
UnknownphenotypeUnknown
phenotype
femalefemale
malemale
Affected individualsAffected
individuals
consanguineous marriage
consanguineous marriage
Female carrier of an x-linked trait
Female carrier of an x-linked trait
marriagemarriage
Extra-maritalmating
Extra-maritalmating
probandproband
diseaseddiseased
progenyprogeny
Stillbornor abortion
Stillbornor abortion
identical (monozygotic)
twins
identical (monozygotic)
twins
Dizygotic twinsDizygotic twins
PEDIGREE
Generations are numbered w/Roman numerals. Within each generation, individuals are numbered from oldest to youngest.
GENERATIONS
SEX-LINKEDRECESSIVE TRAITS
More affected males than females.
Affected grand-father to grand-son thru carrier female.
Females do not manifest the disorder.
Examples of sex-linked recessive traits:
COLOR BLINDNESS
Examples of sex-linked recessive traits:
COLOR BLINDNESS
How it works…How it works…
• Female XX and Male XY.• Traits can be carried on either the X or
Y chromosomes. ( Mostly on the X).• Dominant and recessive laws still
apply.
Problems…Problems…
1. Baldness: Mother XBXb x Father XBY
2. Color Blindness : Mother XbXb x Father XBY
3. Hemophilia: Mother XBXB x Father XbYX
Sex Linked Traits – Punnett Squares
Huntington’s Disease• Woody Guthrie• Arlo Guthrie• Children
DOMINANT Allele DISEASES
Dominant allele -- you have the disease or you don’t
Lobster Foot
Examples of Simple Dominant Disorders• Dwarfism• Polydactyly and Syndactyly• Hypertension• Hereditary Edema
• Chronic Simple Glaucoma – Drainage system for fluid in the eye does not work and pressure builds up, leading to damage of the optic nerve which can result in blindness.
• Huntington’s Disease – Nervous system degeneration resulting in certain and early death. Onset in middle age.
• Neurofibromatosis – Benign tumors in skin or deeper• Familial Hypercholesterolemia – High blood cholesterol and
propensity for heart disease• Progeria – Drastic premature aging, rare, die by age 13. Symptoms
include limited growth, alopecia, small face and jaw, wrinkled skin, atherosclerosis, and cardiovascular problems but mental development not affected.
• Dominant doesn’t necessarily mean commonplace
• Albinism• Achondroplasia
• Both parents can be carriers to have an affected child
• 2 affected parents will usually produce an affected child
RECESSIVE Allele DISEASE
RECESSIVE Allele DISEASE
Examples of Simple Recessive Disorders
• Congenital Deafness• Diabetes Mellitus• Sickle Cell anemia• Albinism• Phenylketoneuria (PKU) – Inability to
break down the amino acid phenylalanine. Requires elimination of this amino acid from the diet or results in serious mental retardation.
• Galactosemia – enlarged liver, kidney failure, brain and eye damage because can’t digest milk sugar
• Cystic Fibrosis – affects mucus and sweat glands, thick mucus in lungs and digestive tract that interferes with gas exchange, lethal.
• Tay Sachs Disease – Nervous system destruction due to lack of enzyme needed to break down lipids necessary for normal brain function. Early onset and common in Ashkenazi Jews; results in blindness, seizures, paralysis, and early death.
Polygenic Inheritance in Polygenic Inheritance in HumansHumans
• includes skin, eye, and hair color• light-skinned X dark-skinned• F1: offspring have intermediate skin
colors• F2: skin color range from light to dark
skin color of the grandparents• Children have intermediate skin color.
Polygenic Traits…• Eye color is determined by more
than one gene • Thus eye color appears to vary on
an almost continuous scale from brown to green to gray to blue
• Eye color is determined by two genes, one controls texture of the iris which refracts light to make blue. A second determines relative abundance of melanin. When a small amount of melanin is present, green eyes result while brown and black eyes result from relatively increasing amounts of melanin
Polygenic Traits…
• Hair color is determined by more than one gene
• Thus hair color appears to vary on an almost continuous scale from black to brown to blond to red
• The brown and black pigment is melanin
• The red pigment is an iron containing molecule
CataractsGlaucomaHereditary deafnessRetinitis pigmentosaSchizophreniaMigrane HeadahesProstate cancerAcute LeukemiaBrain cancerMuscular dystrophyColon cancerAlzheimer’s diseaseFish odor syndrome
CHROMOSOME 1
Colon cancerObesityLiver cancerDiabetes mellitusCleft palateCataractsEpilepsyParkinson’s diseaseMuscular dystrophyPseudohermaphroditismOvarian cancerMicropenis
CHROMOSOME 2
Huntington’s diseaseNight blindnessPhenylketonuriaParkinson’s diseaseAlcoholismRed hairMast cell leukemiaAchondroplasiaDopamine receptorRetinitis pigmentosaHip dysplasia
CHROMOSOME 4
Blood TypeBlood Type
• 4 Types A,B,ABand O4 Types A,B,ABand OParent 1 AlleleParent 1 Allele Parent 2 AlleleParent 2 Allele GenotypeGenotype PhenotypePhenotype
AA AA AAAA AA
AA BB ABAB ABAB
AA OO AOAO AA
BB AA ABAB ABAB
BB BB BBBB BB
BB OO BOBO BB
OO OO OOOO OO
I Am My Own GrandpaI Am My Own Grandpa
• Many, many years ago when I was twenty-three Many, many years ago when I was twenty-three I was married to a widow who was pretty as could be. I was married to a widow who was pretty as could be. This widow had a grown-up daughter who had hair of red. This widow had a grown-up daughter who had hair of red. My father fell in love with her and soon the two were wed.My father fell in love with her and soon the two were wed.
• This made my dad my son-in-law and changed my very life This made my dad my son-in-law and changed my very life For my daughter was my mother, 'cause she was my father's wife. For my daughter was my mother, 'cause she was my father's wife. To complicate the matter even though it brought me joy To complicate the matter even though it brought me joy I soon became the father of a bouncing baby boy.I soon became the father of a bouncing baby boy.
• My little baby then became a brother-in-law to dad My little baby then became a brother-in-law to dad And so he became my uncle though it made me very sad And so he became my uncle though it made me very sad For if he is my uncle then that also makes him brother, For if he is my uncle then that also makes him brother, To the widow's lovely daughter who, of course, was my step-mother.To the widow's lovely daughter who, of course, was my step-mother.
• Father's wife then had a child which kept them on the run, Father's wife then had a child which kept them on the run, And he became my grandchild, 'cause he was my daughter's son; And he became my grandchild, 'cause he was my daughter's son; My wife she is my mother's mother and it makes me blue, My wife she is my mother's mother and it makes me blue, Because although she is my wife, she's my grandmother too.Because although she is my wife, she's my grandmother too.
• Now if she is my grandmother than I'm her grandchild Now if she is my grandmother than I'm her grandchild And every time I think of it, it nearly drives me wild; And every time I think of it, it nearly drives me wild; For now I have become the strangest case you ever saw For now I have become the strangest case you ever saw As husband of my grandmother I am my own grandpa.As husband of my grandmother I am my own grandpa.
• Chorus: Chorus: Oh, I'm my own grandpa, I'm my own grandpa Oh, I'm my own grandpa, I'm my own grandpa It sounds funny, I know, but it really is so It sounds funny, I know, but it really is so Oh, I'm my own grandpa. Oh, I'm my own grandpa.
• Below is a link to the song that can be played in class:Below is a link to the song that can be played in class:• http://www.ziplo.com/grandpa.htmhttp://www.ziplo.com/grandpa.htm
top related