BIOLOGY NOTES GENETICS PART 5 PAGES 198-208, 212-217

Standards: _____ Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance _____ Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, co-dominant, sex-linked, polygenic, and multiple alleles _____ Analyze how heredity and family history can impact personal health 5.6 5.7 5.14

Essential Question: 1. How do genes influence the variety of organisms that exist?

Human Autosomal Disorders Autosome = chromosome pairs 1-22 which contain genes for characteristics not directly related to the ____ of the organism Autosomal disorders can occur in any chromosomes except the _____ chromosomes sex sex

Albinism  Cause: ________________ Lack of pigment in skin, _____ , and eyes Skin and eyes are extremely sensitive to _____ 2. Cystic Fibrosis Cause: _________________ Excess mucus in __________and digestive tract Respiratory and pulmonary problems 2 recessive alleles hair light 2 recessive alleles respiratory

3. Galactosemia Cause: _________________ Inability to breakdown __________ which builds up in body Mental retardation, eye and _____ damage 4. Tay-Sachs disease Cause: ________________ Lipid accumulation in brain cells Death early in childhood. 2 recessive alleles galactose liver 2 recessive alleles

5. Huntington’s disease Cause: _______________ Progressive destruction of muscles and nervous system Destruction of muscles and _______ until death occurs 1 dominant allele nerves

II. Unique Patterns of Inheritance Simple ___________ genetics predicts offspring and parents based on alleles that are only _________ or _________. The majority of organisms, however, are more ________ and show unique patterns of ___________. Mendelian dominant recessive complex inheritance

Incomplete Dominance = type of inheritance in which __ allele is not completely __________ over another the heterozygote is a ______ between the two alleles (completely different heterozygote) 1 dominant blend

e.g. flower color in 4o’clock plants RR = Red RW = Pink WW = White RR * WW = RW (pink) ** since neither allele is more dominant over the other, each allele gets its own letter What type of human traits do you think show incomplete dominance (baby lab)? ** Lip shape, mouth size, size of eyes, eye spacing, hair type, ear size, nose size

B. Multiple Alleles = type of inheritance in which genes have more than __ alleles within a __________ each individual can have only ___ alleles e.g. ABO Blood System 2 population 2 3 alleles = IA, IB, and i IAIA = type A blood IAi = type A blood IAIB = type AB blood IBIB = type B blood IBi = type B blood ii = type O blood (no antigens)

* Who would be the universal donor? * Who would be the universal recepient? ii = type O blood IAIB = type AB blood

C. Codominance = type of inheritance in which both alleles contribute to the __________ both alleles ________ themselves, but not as a ______ e.g. AB Blood Type, Checkered Chickens, Sickle Cell Anemia phenotype express blend IAIA = type A blood (has only A antigens) IBIB = type B blood (has only B antigens) IAIB = type AB blood (has A and B antigens)

e.g. AB Blood Type, Checkered Chickens B = Black b = White Bb = checkered

D. Polygenic Traits = type of inheritance in which ______ are controlled by more than __ gene e.g. eye color, hair color, skin color traits 1

E. Sex-Linked Genes = type of inheritance in which genes with particular ______ are located on the sex _____________ (X or Y) males are ____ while females are ____ in males, any trait linked to the ___ chromosome will be ___________ even if they are recessive traits chromosomes XY XX X expressed

1. Color-Blindness caused by a recessive ______ on the ___ chromosome 1 in 10 males have red-green colorblindness 1 in 100 females have red-green colorblindness allele X

e.g. XB = normal Xb = colorblind XBXB = normal female XBXb XBY = normal male XbXb = colorblind female XbY = colorblind male

2. Hemophilia caused by a recessive ______ on the ___ chromosome 1 in 10,000 males have the disease in this disease, blood clotting enzymes are _______ small bruises and cuts may cause excessive _________ even into death allele X absent bleeding

e.g. What would be the chances of having a Hemophiliac son if XHXh * XHy?

III. Human Heredity Karyotype = a chart that shows all pairs of _____________ in order taken during _______ when the chromosomes formed (during prophase) humans have ___ chromosomes that are organized into ___ pairs each pair has the same _____ of genes but may have different _______ chromosomes mitosis 46 23 type alleles

in each pair, one chromosome comes from _____ and one from ____ sex chromosomes = the _____ set of chromosomes that determines the _______ of the human ____ for males and ____ for females mom dad 23rd gender XX XY

D. Sex Chromosomal Disorders Nondisjunction = during meiosis, ____________ chromosomes fail to separate meaning gametes with too ______ or too ____ chromosomes homologous few many

results in severe mental retardation 1. Down’s Syndrome also known as ________ 21 because there are __ #21 chromosomes results in severe mental retardation 2. Klinefelter’s Syndrome (XXY) have an extra ___ chromosome prevents individuals from reproducing trisomy 3 X

3. Turner’s Syndrome (XO) have only ___ sex chromosome which is an ___ unable to develop sex organs at all 1 X