Chromosomal Abnormalities (11.3) State Standard 2C. Using Mendel’s laws, explain the role of meiosis in reproductive variability. 2D. Describe the relationships between changes in DNA and potential appearance of new traits

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. Used to identify chromosome abnormalities

Normal Karyotype

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 Nondisjunction on autosomes (non-sex chromosomes – 1-22) can cause: Down Syndrome (Trisomy 21) Patau Syndrome (Trisomy 13) Edwards Syndrome (Trisomy 18)

Nondisjunction Cont’d Chapter 11 Complex Inheritance and Human Heredity 11.3 Chromosomes and Human Heredity Nondisjunction Cont’d Nondisjunction on sex chromosomes can cause… Turner Syndrome (female w/ only 1 X chromosome Klinefelter’s Syndrome (male w/ an extra X chromosome

Nondisjunction

Chapter 11 Complex Inheritance and Human Heredity

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

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

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