Chapter 11 Complex Inheritance and Human Heredity Section 1: Basic Patterns of Human Inheritance Section 2: Complex Patterns of Inheritance Section 3: Chromosomes and Human Heredity

Recessive Genetic Disorders Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Recessive Genetic Disorders A recessive trait is expressed when the individual is homozygous recessive for the trait.

Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Cystic Fibrosis Affects the mucus-producing glands, digestive enzymes, and sweat glands Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat. Without sufficient chloride ions in the cells, a thick mucus is secreted.

Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Albinism Caused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes White hair Very pale skin Pink pupils

Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Tay-Sachs Disease Caused by the absence of the enzymes responsible for breaking down fatty acids called gangliosides Gangliosides accumulate in the brain, inflating brain nerve cells and causing mental deterioration.

Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Galactosemia Recessive genetic disorder characterized by the inability of the body to digest galactose.

Dominant Genetic Disorders These diseases are caused when an individual is homozygous dominant or heterozygous In order to NOT HAVE THESE DISEASES the normal person is homozygous recessive

Dominant Genetic Disorders Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Dominant Genetic Disorders Huntington’s disease affects the nervous system. Achondroplasia is a genetic condition that causes small body size and limbs that are comparatively short. (this is a type of dwarfism)

11.1 Basic Patterns of Human Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance

Chapter 11 Complex Inheritance and Human Heredity

Pedigrees 11.1 Basic Patterns of Human Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Pedigrees A diagram that traces the inheritance of a particular trait through several generations of the same family

Inferring Genotypes Predicting Disorders Chapter 11 Complex Inheritance and Human Heredity 11.1 Basic Patterns of Human Inheritance Inferring Genotypes Knowing physical traits can determine what genes an individual is most likely to have. Scientists can determine if a trait is dominant or recessive Predicting Disorders Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and ascertain genotypes.

Incomplete Dominance 11.2 Complex Patterns of Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Incomplete Dominance The heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes. (it is a mix of physical appearance between the dominant and the recessive)

Both alleles are expressed in the heterozygous condition. Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Codominance Both alleles are expressed in the heterozygous condition.

Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Sickle-cell Disease Normal red blood cell 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 7766x

Sickle-cell disease and Malaria In Africa there is a high number of people who have the sickle-cell allele. People who are heterozygous for sickle-cell have a higher resistance to malaria. They go on to reproduce and pass on the sickle-cell trait.

ABO blood groups have three forms of alleles. Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Multiple Alleles Blood groups in humans (this shows both multiple alleles and codominance) ABO blood groups have three forms of alleles.

Multiple alleles can demonstrate a hierarchy of dominance. Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Coat Color of Rabbits Multiple alleles can demonstrate a hierarchy of dominance. In rabbits, four alleles code for coat color: C, cch, ch, and c. C>cch> ch>c (this shows that one is dominant to the next with “c” being least dominant) There are 10 possible genotypes and four phenotypes for rabbit fur color Option 2 (continued on the next slide)

Coat Color of Rabbits 11.2 Complex Patterns of Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Coat Color of Rabbits Chinchilla Option 2 Albino Light gray Dark gray Himalayan

Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Epistasis Variety is the result of one allele hiding the effects of another allele. eebb eeB_ E_bb E_B_ No dark pigment present in fur Dark pigment present in fur

Labrador Coat Color There are two sets of alleles (“E” and “B”) that determine whether the fur will be dark or not. If the dog has Ee or EE it will make the fur color dark (it is written as Eebb or EEbb) If the dog has ee then the fur coat will be light (eebb, eeBb, eeBB) and produce a yellow coat

Sex chromosomes determine an individual’s gender. Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Sex Determination Sex chromosomes determine an individual’s gender. Autosomes are all the other chromosomes that determine everything else. (ie. Body cells)

Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Dosage Compensation The X chromosome carries a variety of genes that are necessary for the development of both females and males. (Thus, it is larger than the Y chromosome) The Y chromosome mainly has genes that relate to the development of male characteristics.

Chromosome inactivation Coat color of the calico cat is determined by which X chromosome is deactivated. If the X chromosome that carries the dark coat color is inactivated, the cat will have orange coloring. If the X chromosome that carries the orange coat color is inactivated, the cat will have black spots. Barr bodies: the inactivated X chromosome in females

Sex-Linked Traits 11.2 Complex Patterns of Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Sex-Linked Traits Genes located on the X chromosome that control traits Since males have only 1 X chromosome they are affected by recessive X-linked traits Females are less likely to express a recessive trait because she has two X chromosomes. One of the X chromosomes can mask the affect of the trait. Sex-Linked Traits

Sex-Linked Traits 11.2 Complex Patterns of Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Sex-Linked Traits Red-green color blindness This is a recessive X-linked trait. A male only needs one copy of this allele in order to be colorblind. A female would need to have two copies of the recessive allele. Thus it is very rare to find a color blind female. Sex-Linked Traits

Hemophilia Another recessive sex-linked disorder characterized by delayed clotting of the blood. Very rare in females because she would need to have both X chromosomes with the recessive trait.

Polygenic Traits 11.2 Complex Patterns of Inheritance Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Polygenic Traits Polygenic traits arise from the interaction of multiple pairs of genes. This is really how height, eye color and fingerprints are inherited.

Environmental Influences on phenotype Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Environmental Influences on phenotype Environmental factors Diet and exercise Sunlight and water (flowering in plants) Temperature (arctic fox)

Chapter 11 Complex Inheritance and Human Heredity 11.2 Complex Patterns of Inheritance Twin Studies Helps scientists separate genetic contributions from environmental contributions Traits that appear frequently in identical twins are at least partially controlled by heredity. Traits expressed differently in identical twins are strongly influenced by environment.

Images of chromosomes stained during metaphase Chapter 11 Complex Inheritance and Human Heredity 11.3 Chromosomes and Human Heredity Karyotype Studies Karyotype—micrograph in which the pairs of homologous chromosomes are arranged in decreasing size. Images of chromosomes stained during metaphase Chromosomes are arranged in decreasing size to produce a micrograph.

Telomere caps consist of DNA associated with proteins. Chapter 11 Complex Inheritance and Human Heredity 11.3 Chromosomes and Human Heredity Telomeres Telomere caps consist of DNA associated with proteins. Serves a protective function for the structure of the chromosome They might also be involved in aging and cancer

Cell division during which sister chromatids fail to separate properly Chapter 11 Complex Inheritance and Human Heredity 11.3 Chromosomes and Human Heredity Nondisjunction Cell division during which sister chromatids fail to separate properly If this occurs during Meiosis I or II then the resulting gametes will not have the correct number of chromosomes Down syndrome: nondisjunction occurred on chromosome 21. The result is short stature, heart defects, and mental disability

Nondisjunction Nondisjunction occurs in both autosomes (body cells) and in gametes

Centromere Sister chromatids Pair of homologous chromosomes 5 Centromere Sister chromatids Figure 8.19 Preparation of a karyotype from a blood sample. Pair of homologous chromosomes 5

Figure 8.20B A child with Down syndrome. This child shows characteristic facial features associated with Down syndrome, including a round face and flattened nose bridge.

Chapter 11 Complex Inheritance and Human Heredity

Chapter Resource Menu Chapter Diagnostic Questions Complex Inheritance and Human Heredity Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding feature.

Identify the disease characterized by the absence of melanin. Chapter 11 Complex Inheritance and Human Heredity Chapter Diagnostic Questions Identify the disease characterized by the absence of melanin. albinism cystic fibrosis galactosemia Tay-Sachs A B C D CDQ 1

An individual with Tay-Sachs disease would be Chapter 11 Complex Inheritance and Human Heredity Chapter Diagnostic Questions An individual with Tay-Sachs disease would be identified by which symptom? excessive mucus production an enlarged liver a cherry-red spot on the back of the eye vision problems A B C D CDQ 2

Under what circumstances will a recessive trait be expressed? Chapter 11 Complex Inheritance and Human Heredity Chapter Diagnostic Questions Under what circumstances will a recessive trait be expressed? A recessive allele is passed on by both parents. One parent passes on the recessive allele. The individual is heterozygous for the trait. There is a mutation in the dominant gene. A B C D CDQ 3

Chapter 11 Complex Inheritance and Human Heredity 11.1 Formative Questions Which of Dr. Garrod’s observations about alkaptonuria was most critical to his determination that it is a genetic disorder? It appears at birth and runs in families. It is linked to an enzyme deficiency. It continues throughout a patient’s life, affecting bones and joints. It is caused by acid excretion and results in black urine. A B C D FQ 1

Which is the genotype of a person who is Chapter 11 Complex Inheritance and Human Heredity 11.1 Formative Questions Which is the genotype of a person who is a carrier for a recessive genetic disorder? DD Dd dd dE A B C D FQ 2

Chapter 11 Complex Inheritance and Human Heredity 11.1 Formative Questions Albinism is a recessive condition. If an albino squirrel is born to parents that both have normal fur color, what can you conclude about the genotype of the parents? at least one parent is a carrier both parents are carriers both parents are homozygous recessive at least one parent is homozygous dominant A B C D FQ 3

Chapter 11 Complex Inheritance and Human Heredity 11.2 Formative Questions When a homozygous male animal with black fur is crossed with a homozygous female with white fur, they have offspring with gray fur. What type of inheritance does this represent? dosage compensation incomplete dominance multiple alleles sex-linked A B C D FQ 4

Of the 23 pairs of chromosomes in human Chapter 11 Complex Inheritance and Human Heredity 11.2 Formative Questions Of the 23 pairs of chromosomes in human cells, one pair is the _______. autosomes Barr bodies monosomes sex chromosomes A B C D FQ 5

Which is an example of a polygenic trait? Chapter 11 Complex Inheritance and Human Heredity 11.2 Formative Questions Which is an example of a polygenic trait? blood type color blindness hemophilia skin color A B C D FQ 6

What does a karyotype show? Chapter 11 Complex Inheritance and Human Heredity 11.3 Formative Questions What does a karyotype show? The blood type of an individual. The locations of genes on a chromosome. The cell’s chromosomes arranged in order. The phenotype of individuals in a pedigree. A B C D FQ 7

What is occurring in this diagram? Chapter 11 Complex Inheritance and Human Heredity 11.3 Formative Questions What is occurring in this diagram? multiple alleles nondisjunction nonsynapsis trisomy A B C D FQ 8

What condition occurs when a person’s cells Chapter 11 Complex Inheritance and Human Heredity 11.3 Formative Questions What condition occurs when a person’s cells have an extra copy of chromosome 21? Down syndrome Klinefelter’s syndrome Tay-Sachs syndrome Turner’s syndrome A B C D FQ 9

Chapter 11 Complex Inheritance and Human Heredity Chapter Assessment Questions Use the figure to describe what the top horizontal line between numbers 1 and 2 indicates. 1 and 2 are siblings 1 and 2 are parents 1 and 2 are offspring 1 and 2 are carriers A B C D CAQ 1

Which is not an allele in the ABO blood group? IA IO IB i Chapter 11 Complex Inheritance and Human Heredity Chapter Assessment Questions Which is not an allele in the ABO blood group? IA IO IB i A B C D CAQ 2

Down Syndrome results from what change in chromosomes? Chapter 11 Complex Inheritance and Human Heredity Chapter Assessment Questions Down Syndrome results from what change in chromosomes? one less chromosome on pair 12 one extra chromosome on pair 21 one less chromosome on pair 21 one extra chromosome on pair 12 A B C D CAQ 3

If a genetic disorder is caused by a dominant Chapter 11 Complex Inheritance and Human Heredity Standardized Test Practice If a genetic disorder is caused by a dominant allele, what is the genotype of those who do not have the disorder? heterozygous homozygous dominant homozygous recessive A B C STP 1

RR Rr rr Standardized Test Practice Chapter 11 Complex Inheritance and Human Heredity Standardized Test Practice Analyze this pedigree showing the inheritance of a dominant genetic disorder. Which would be the genotype of the first generation father? A B C RR Rr rr STP 2

Standardized Test Practice Chapter 11 Complex Inheritance and Human Heredity Standardized Test Practice Shorthorn cattle have an allele for both red and white hair. When a red-haired cow is crossed with a white-haired bull, their calf has both red and white hairs scattered over its body. What type of inheritance does this represent? A B C D codominance dosage compensation epistasis sex-linked STP 3

Males have only one X chromosome. Males have two X chromosomes. Chapter 11 Complex Inheritance and Human Heredity Standardized Test Practice Why are males affected by recessive sex-linked traits more often than are females? Males have only one X chromosome. Males have two X chromosomes. Males have only one Y chromosome. The traits are located on the Y chromosomes. A B C D STP 4

Chapter 11 Complex Inheritance and Human Heredity Standardized Test Practice A carrier of hemophilia and her husband, who is unaffected by the condition, are expecting a son. What is the probability that their son will have hemophilia? 25% 50% 75% 100% A B C D STP 5

Glencoe Biology Transparencies Chapter 11 Complex Inheritance and Human Heredity Glencoe Biology Transparencies

Chapter 11 Complex Inheritance and Human Heredity Image Bank

Section 1 Vocabulary carrier pedigree Chapter 11 Complex Inheritance and Human Heredity Vocabulary Section 1 carrier pedigree

Section 2 Vocabulary incomplete dominance codominance multiple alleles Chapter 11 Complex Inheritance and Human Heredity Vocabulary Section 2 incomplete dominance codominance multiple alleles epistasis sex chromosome autosome sex-linked trait polygenic trait

Section 3 Vocabulary karyotype telomere nondisjunction Chapter 11 Complex Inheritance and Human Heredity Vocabulary Section 3 karyotype telomere nondisjunction

Visualizing Nondisjunction Chapter 11 Complex Inheritance and Human Heredity Animation Visualizing Nondisjunction

Chapter 11 Complex Inheritance and Human Heredity