Science Warm-up 10/28/2012 Write a paragraph that describes what physical abilities a professional soccer player should have. Also, include what physical features are not important for a soccer player to have. Thank you for completing this individually and quietly.

Chapter 11: Complex Inheritance and Human Heredity Aaron Wood By PresenterMedia.comPresenterMedia.com

Overview Section 1: Basic Patterns of Human Inheritance Section 2: Complex Patterns of Inheritance Section 3: Chromosomes and Human Heredity

Section 1: Basic Patterns of Human Inheritance Overview Recessive genetic disorders Dominant genetic disorders Pedigrees Analyzing pedigrees

Recessive Genetic Disorders A recessive trait is expressed when the individual is homozygous recessive for the trait. Ex) gg

Cystic Fibrosis Affects the mucus-producing glands, digestive enzymes, and sweat glands. Mucus is extremely thick, and extremely hard to get rid of. 1 in 3500 chances Treatment is daily cleaning of the lungs, and medicine.

Albinism Genes do not produce normal amounts of the pigment melanin. 1 in 17,000 occurrence

Galactosemia Inability to break down galactose Mental disabilities, enlarged liver, and kidney failure. No cure 1 in 60,000 occurence

Tay-Sacs Disease Absence of a substance that breaks down fatty substances. Causes a buildup of fatty deposits in the brain, and mental delaying. 1 in 2,500 occurrence, mainly affects those with Jewish descent.

Dominant Genetic Disorders Huntington’s disease Achondroplaisia

Huntington’s Disease A gene affecting neurological function is defective. Decline of mental and neurological functions, and the ability to move deteriorates. 1 in 10,000 occurance

Achondroplasia A gene that affects bone growth is abnormal. Effects: short arms and legs, large head

Pedigrees A pedigree is a diagram that traces the inheritance of a particular trait through several generations. Compared to a family tree, but for a characteristic of disease. Males are squares, females are circles. Normal is typically a blank circle, carriers are half-filled, and expressers are completely filled.

Analyzing Pedigrees Inferring Genotypes Knowing physical traits can determine what genes an individual is most likely to have. Predicting Disorders Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and infer genotypes.

Section 2: Complex Patterns of Inheritance Overview Incomplete Dominance Codominance Multiple Alleles Epistasis Sex Determination Sex-linked traits

Incomplete Dominance This is when a heterozygous individual’s phenotype is an intermediate phenotype between the two homozygous phenotypes.

Codominance This situation occurs when both alleles are expressed in the heterozygous condition Ex) Sickle-cell disease

Sickle-cell disease Changes in hemoglobin cause red blood cells to change to a sickle shape. People who are heterozygous for the trait have both normal and sickle- shaped cells. Sickle cell Normal red blood cell

These sickle-cells are unable to carry as much oxygen as a normal cell. They also tend to block circulation in the hands and feet. Why is there such an overlap with sickle-cell and malaria?

Individuals that are heterozygous for sickle-cell disease also have a higher resistance for malaria. These individuals are more likely to survive and pass on the sickle-cell trait to offspring.

Multiple Alleles Some forms of inheritance are determined by more than two alleles. Ex) blood groups in humans (ABO)

Epistasis Occurs when one allele hides the effects of another allele. This is the cause of coat color in Labrador retrievers. No dark pigment present in fur Dark pigment present in fur eebb eeB_ E_bbE_B_

Sex Determination Sex chromosomes determine an individual’s gender. For humans these are either the X chromosome and Y chromosome.

Sex-linked Traits Genes located on the X chromosome Color blindness Hemophilia

Color blindness The trait for red-green color blindness is a recessive X-linked trait. This is very uncommon among females.

Hemophilia A recessive sex-linked disorder, is characterized by delayed clotting of the blood. Famous pedigree based on Queen Victoria of England ( )

Section 3: Complex Inheritance and Human Heredity Overview Environmental Influences Karyotypes Telomeres Nondisjunction

Environmental Influences The following things can impact the expression of certain characteristics Environmental factors Diet and exercise Sunlight and water Temperature

Karyotype Studies Micrograph in which the pairs of homologous chromosomes are arranged in decreasing size.

Karyotypes can be used to predict and test for genetic alterations. Chromosomes are stained during metaphase.

Telomeres Telomere caps consist of DNA associated with proteins Serves as a protective function for the structure of a chromosome.

Nondisjunction Cell division when sister chromatids fail to separate properly. Causes disorders such as Down’s Syndrome.

Down’s Syndrome Also known as trisomy 21. Individuals receive an extra copy of the 21 st chromosome. Causes mental delaying and stunted growth.

Fetal Genetic Testing There are different ways to test the genetic makeup of a fetus in the womb. Amniocentesis Chorionic villus sampling Fetal blood sampling

Amniocentesis Prenatal diagnosis of chromosomal abnormalities, and fetal infections.

Chorionic villus sampling Removal of a small piece of the placenta tissue to determine chromosomal or genetic abonormalities.

Fetal blood sampling Testing of a small amount of blood from the fetus to determine certain characteristics.