Genetics
Vocabulary (Chapter 14): character, trait, true-breeding, homozygous, heterozygous, hybridization, Law of Segregation, alleles, dominant, recessive, Punnett square, phenotype, genotype, testcross, monohybrid cross, dihybrid cross, Law of Independent Assortment, complete dominance, incomplete dominance, codominance, Tay-Sachs disease, pleiotropy, epistasis, multiple alleles, polygenic inheritance, quantitative characters, multifactorial characters, pedigree, carriers, albinism, cystic fibrosis, sickle-cell disease, Huntington's disease, achondroplasia, amniocentesis, chorionic villus sampling (CVS)
Objectives:
After attending lectures and studying the chapter, the student should be able to:
1. Define diploid and state which cells in your body are diploid.
2. State the number of chromosomes in your diploid cells and state how many of those
chromosomes came from your father and how many came from your mother.
3. Distinguish between autosomes and sex chromosomes, state how many of each are in
your diploid cells, and state the sex-chromosome combinations that are in human males
and human females.
4. Describe an individual's karyotype.
5. Explain the relationship between genes and chromosomes.
6. Explain the relationship between genes and alleles.
7. Describe linked genes.
8. State the number of alleles you have for each gene in your diploid cells and state how
many of those alleles came from your father and how many came from your mother.
9. Distinguish between an individual's phenotype and genotype.
10. Distinguish between autosomal traits and sex-linked traits.
11. Distinguish between complete dominance, incomplete dominance, and codominance.
12. Describe the multiple allele inheritance pattern of the human ABO blood type.
13. Describe and give an example of polygenic inheritance.
14. Describe and give an example of epistasis.
15. Describe and give an example of pleiotropy.
16. Describe a pedigree and use a pedigree chart to determine patterns of inheritance.
17. List the 4 steps used in genetics problems to determine offspring possibilities.
18. Use the 4-step genetics-problem-solving process to work single-gene cross and 2-gene
cross genetics problems, including monohybrid and dihybrid crosses.
19. Give examples of and work genetics problems relating to each of the following human
single-gene traits:
a. autosomal and sex-linked traits(chapter 15);
b. normal traits and genetic disorders;
c. traits with multiple alleles in the population;
d. recessively-inherited and dominantly-inherited traits; and,
e. traits with complete dominance, incomplete dominance, and codominance.
Vocabulary (chapter 15): sex-linked genes, duchene muscular dystrophy, hemophilia, Barr body, linked genes, nondisjunction, aneuploidy, monosomic, trisomic, polyploidy, deletion, duplication, inversion, translocation, Down syndrome, Turner syndrome, Klinefelter syndrome
20. Describe meiotic nondisjunction and explain how this can lead to human chromosomal
abnormalities.
21. Describe the human chromosomal abnormalities that lead to Down syndrome, Turner
syndrome, and Klinefelter syndrome.
22. Describe genomic imprinting and how it affects phenotypic expression of genes.
23. Understand linked genes and why they do not show the same pattern of inheritance as genes located on different chromosomes.
| 1708970908 | The Law of segregation | Mendel's first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation. |  | 0 |
| 1708970909 | Allele | Any of the alternative versions of a gene that may produce distinguishable phenotypic effects. |  | 1 |
| 1708970922 | Dominant Allele | An allele that is fully expressed in the phenotype of a heterozygote. | 2 | |
| 1708970923 | Recessive Allele | An allele whose phenotypic effect is not observed in a heterozygote. | 3 | |
| 1708970910 | Genotype | The genetic makeup, or set of alleles, of an organism. |  | 4 |
| 1708970911 | Phenotype | The EXPRESSED/observable physical and physiological traits of an organism, which are determined by its genetic makeup. | | 5 |
| 1708970924 | The Law of Segregation | Mendel's first law, stating that the two alleles in a pair segregate (separate from each other) into different gametes during gamete formation. | 6 | |
| 1708970912 | Homozygous | Having two identical alleles for a given gene. |  | 7 |
| 1708970913 | Heterozygous | Having two different alleles for a given gene. |  | 8 |
| 1708970914 | Phenotype | Expressed. The observable physical and physiological traits of an organism, which are determined by its genetic makeup. |  | 9 |
| 1708970915 | Genotype | The genetic makeup, or set of alleles, of an organism. |  | 10 |
| 1708970916 | Testcross | Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of phenotypes in the offspring reveals the unknown genotype. |  | 11 |
| 1708970925 | The Law of Independent Assortment | Mendel's second law, stating that each pair of alleles segregates, or assorts, independently of each other pair during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes or when they are far enough apart on the same chromosome to behave as though they are on different chromosomes. | 12 | |
| 1708970917 | Monohybrids | An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aa. |  | 13 |
| 1708970918 | Monohybrid Cross | A cross between two organisms that are heterozygous for the character being followed (or the self-pollination of a heterozygous plant). |  | 14 |
| 1708970919 | Dihybrids | An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb. |  | 15 |
| 1708970920 | Dihybrid Cross | A cross between two organisms that are each heterozygous for both of the characters being followed (or the self-pollination of a plant that is heterozygous for both characters). |  | 16 |
| 1708970926 | Complete dominance | The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable. | 17 | |
| 1708970921 | Incomplete dominance | The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele. |  | 18 |
| 1708970927 | Codominance | The situation in which the phenotypes of both alleles are exhibited in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways. | 19 | |
| 1708970928 | Tay-Sachs Disease | A human genetic disease caused by a recessive allele for a dysfunctional enzyme, leading to accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth, followed by death within a few years. | 20 | |
| 1708970929 | Polygenic Inheritance | An additive effect of two or more genes on a single phenotypic character. | 21 | |
| 1708970930 | Pedigree | A diagram of a family tree with conventional symbols, showing the occurrence of heritable characters in parents and offspring over multiple generations. | 22 | |
| 1708970931 | Carriers | In genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder. The heterozygote is generally phenotypically normal for the disorder but can pass on the recessive allele to offspring. | 23 | |
| 1708970932 | Sex-Linked Gene | A gene located on either sex chromosome. Most sex-linked genes are on the X chromosome and show distinctive patterns of inheritance; there are very few genes on the Y chromosome. | 24 | |
| 1708970933 | Nondisjunction | An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other. | 25 | |
| 1708970934 | Deletion | (1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene. | 26 | |
| 1708970935 | Duplication | An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such taht a portion of a chromosome is duplicated. | 27 | |
| 1708970936 | Inversion | An aberration in chromosome structure resulting from reattachment of a chromosomal fragment in a reverse orientation to the chromosome from which it originated. | 28 | |
| 1708970937 | Translocation | (1) An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. (2) During protein synthesis, the third stage in the elongation cycle, when the RNA carrying the growing polypeptide moves from the A site to the P site on the ribosome. (3) The transport of organic nutrients in the phloem of vascular plants. | 29 | |
| 1708970938 | Down Syndrome | A humaan genetic disease usually caused by the presence of an extra chromosome 21; characterized by developmental delays and heart and other defects that are generally treatable or non-life threatening. | 30 |
