4consanguineous marriage Female carrier of an x-linked trait probandconsanguineous marriageFemale carrier of an x-linked traitmarriageExtra-maritalmatingidentical(monozygotic)twinsDizygotic twinsmalediseasedAffectedindividualsprogenycarrierStillbornor abortion?Unknownphenotype
13DOMINANT Allele DISEASES Huntington’s DiseaseWoody GuthrieArlo GuthrieChildrenLobster FootDominant allele -- you have the disease or you don’t
14Examples of Simple Dominant Disorders DwarfismPolydactyly and SyndactylyHypertensionHereditary EdemaChronic 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 deeperFamilial Hypercholesterolemia – High blood cholesterol and propensity for heart diseaseProgeria – 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.
15RECESSIVE Allele DISEASE AlbinismAchondroplasiaBoth parents can be carriers to have an affected child2 affected parents will usually produce an affected childDominant doesn’t necessarily mean commonplace
16Examples of Simple Recessive Disorders Congenital DeafnessDiabetes MellitusSickle Cell anemiaAlbinismPhenylketoneuria (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 sugarCystic 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.
18Polygenic Inheritance in Humans includes skin, eye, and hair colorlight-skinned X dark-skinnedF1: offspring have intermediate skin colorsF2: skin color range from light to dark skin color of the grandparentsChildren have intermediate skin color.
19Polygenic 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 blueEye 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
20Polygenic 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 redThe brown and black pigment is melaninThe red pigment is an iron containing molecule
24Blood Type 4 Types A,B,ABand O A AA B AB O AO BB BO OO Parent 1 Allele GenotypePhenotypeAAABABOAOBBBOOO
25I Am My Own Grandpa Many, many years ago when I was twenty-three I was married to a widow who was pretty as could be. 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.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. To complicate the matter even though it brought me joy I soon became the father of a bouncing baby boy.My little baby then became a brother-in-law to dad And so he became my uncle though it made me very sad 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.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; My wife she is my mother's mother and it makes me blue, Because although she is my wife, she's my grandmother too.Now if she is my grandmother than I'm her grandchild And every time I think of it, it nearly drives me wild; For now I have become the strangest case you ever saw As husband of my grandmother I am my own grandpa.Chorus: Oh, I'm my own grandpa, I'm my own grandpa It sounds funny, I know, but it really is so Oh, I'm my own grandpa. Below is a link to the song that can be played in class: