WORKSHEET BIO 208 Unit 2. Also review list of objectives, notes, textbook, and homework assignments

Transcription

1 Also review list of objectives, notes, textbook, and homework assignments 1. Animals can teach us genetics. Match Heterozygotes exhibit two distinct proteins on red blood cells Show a dominant and recessive relationship An allelic series A dominant homozygote is lethal Coat coloration is determined by 2 distinct genes Shows variable expressivity A qualitative, or continuous, trait involving polygenes Females mosaics for X-linked heterozygous color genes A. Manx cat B. Coat coloration cats C. Labrador retriever dogs D. Piebald spotting in beagles E. MN antigens F. A and O blood alleles G. Calico cat H. Height of an individual 2. If Mendel only knew. Fill in EPISTASIS DOMINANCE ALLELE CODOMINANCE INCOMPLETE DOMINANCE PENETRANCE INDEPENDENT ASSORTMENT EXPRESSIVITY RANDOM SEGREGATION a. The expression of both alleles of a heterozygous gene pair is called: b. The degree to which a genotype is expressed in the phenotype: c. The suppression of one gene by another non allelic gene : d. The % of individuals of a genotype that show the expected phenotype: e. Each gamete receives one allele of a gene : f. When heterozygous genotype results in phenotype intermediate to the two alleles_ g. Alleles of 1 gene pair inherited independently from those of another gene pair h. An alternative form of a gene: i. Expression of one allele to the exclusion of the other in a heterozygote: 3. Examine pedigree Why is this NOT a Y linked trait? Could this be an X linked trait? Is this inherited in an autosomal dominant or autosomal recessive manner? 4. Fill in XY female Cri du Chat Down syndrome XX male Anhydrotic ectodermal dysplasia Neurofibromatosis Patau syndrome Hemophilia Polydactyly Phenylketonuria Achondroplasia Alkaptonuria a. Male, small testes, infertility b. Female may not have ovaries or a uterus c. Female heterozygotes have patches of skin that lack sweat glands d. Inability to clot blood due to lack of a clotting factor e. Dominant allele results in extra fingers and toes f. Recessive allele prevents metabolism of phenylalanine g. Dominant allele affects cartilage growth needed for bone lengthening h. Retardation, higher risk of Alzheimer disease i. Babies usually do not live beyond a year, deaf, blind j. Microcephaly, abnormal larynx anatomy k. Metabolic disease part of phe pathway, black urine l. 5 disorders that can be detected by karyotype m. Tumors on skin, connective tissue, and organs

2 5. Do you know your numbers? a. number of chromosomes in a human diploid cell b. number of chromosomes in a human haploid cell c. number of chromosomes in a human Turner syndrome cell d. number of chromosomes in a human trisomic cell e. number of chromosomes in a human triploid cell f. number of chromosomes in a human cell with a Robertsonian fusion g. number of chromosomes in a human fertilized egg h. number of chromosomes in a normal human sperm 6. Ploidy, somy, and more Fill in: RECIPROCAL TRANSLOCATION MONOPLOID TRIPLOID LOCUS MONOSOMY TRISOMY TETRAPLOID BARR BODY a. Position a gene occupies on a chromosome b. X chromosome in mammals seen as heterochromatin c. Aberrant chromosome number in which normally diploid cell has 3 copies of 1 chromosome d. An exchange of non-homologous chromosomes e. Aberrant chromosomal condition in which cell has 1 copy of a chromosome and 2 copies of all others f. An individual possessing 4 sets of chromosomes 7. It is probable that a probability question is in the future From the cross AaBbccDdEeff X AABbCcDdeeFf what is the probability of obtaining the genotype AabbCcDDEeff in the progeny? 8. Epistasis with two genes In horses, a dominant B gives horse a black color, and a b gives horse a chestnut color. When a dominant W is present in the second gene pair, the horse will be white no matter what. If the second gene pair is ww, then the horse will be the color of whatever the first gene pair encodes. If a heterozygous white (BbWw) mare is crossed with a heterozygous white (BbWw) stallion, what could the offspring's phenotype and genotype be? 9. Let s not forget human sex.. Arrange in the correct chronological order: TDF, SRY, testosterone, male embryo, testes, Y chromosome 10. Fly sex In Drosophila sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. Female ratio is 1 or greater, males have a ratio of 0.5 or less. Identify sex of following flies a. XY fly with 2 sets of autosomes b. XXY fly with 2 sets of autosomes c. XX fly with 3 sets of autosomes 11. And bird sex.. In birds, the male is the homogametic sex. Females are ZW. A dominant sex-linked allele, Z S gives silver feather color. Z s gives gold. Mate a silver female with a gold male. How can you identify male and female offspring by feather color alone?

3 12. Who did it? a. Random X-chromosome inactivation Edwards b. Characterized trisomy 21 Klinefelter c. Characterized trisomy 18 Barr d. Discovered independent assortment Mendel e. Chromosomal theory of inheritance Down f. Characterized XXY males Sutton, Boveri 13. Deletion, Translocation, Inversion, Duplication, OR Mosaicism? a. Involved in 46, 5pb. May result in a position effect which affects gene expression c. May result in pseudodominance of an allele which is normally recessive to a dominant allele d. Two genetically distinct populations of cells in a single individual e. Will result in abnormal gamete formation (more than one answer) f. Involved in familial Down syndrome g. Lethal if it occurs in the same region of two homologous chromosomes h. No loss or gain of genetic material is involved (2 answers) i. Cell will have 45 chromosomes j. Increase of genetic material, may be tandem or reverse k. 46, XX/45, X (one individual) 14. Fill in the blanks on the pathway for phenylalanine metabolism. The arrows represent a mutant enzyme (and corresponding gene) that does not function in the pathway. a. Name of disease b. Why disease kills brain cells c. Name of pigment d. Black urine disorder name 15. List three modes of inheritance possible for this trait. Show your reasoning by indicating possible genotypes for each individual I II

4 16. MORE? a. When true-breeding tall stem pea plants are crossed with true-breeding short stem pea plants, all of the plants, and 3/4 of the plants had tall stems. Therefore, tall stems are dominant b. A cross between two F1-hybrid pea plants having yellow seeds will yield what percent green-seeded plants in the F2 generation? Yellow seeds are dominant to green. c. To identify genotype of yellow-seeded pea plants as either homozygous dominant (YY) or heterozygous (Yy), you could do a test cross with plants of genotype. d. What is the probability that a woman with cystic fibrosis (an autosomal recessive disease) and normal male whose parents are homozygous dominant have a child with cystic fibrosis? e. Why not possible for colorblind man who mates with normal woman (X C X C ) to have colorblind son? f. Maple syrup disease is a rare genetic (inherited) disease. This disorder of metabolism causes the baby s urine to assume the odor of maple syrup. Two individuals, heterozygous for the disease (phenotypically normal) have 10 children. How many children are expected to exhibit the disorder? g. In Mendel's experiments, if gene for tall (T) plants was incompletely dominant over gene for short (t) plants, what would be the result of crossing two Tt plants? h. A genetic cross of inbred snapdragons with red flowers with inbred snapdragons with white flowers resulted in F1-hybrid offspring - all pink. When the F1 plants were self-pollinated, the resulting F2- generation plants had a phenotypic ratio of 1 red: 2 pink: 1 white. The most likely explanation is: i. A woman with type A blood and a man with type B blood could potentially have offspring with which of the following blood types? j. A pea plant is heterozygous for both seed shape and seed color. S allele is round shape.; s is allele for the recessive, dented shape. Y is allele for dominant, yellow color; y is allele for recessive, green color. What will be the distribution of these two alleles in this plant's gametes? k. Which of the following genetic crosses would be predicted to give a phenotypic ratio of 9 :3:3: 1? SSYY x ssyy or SsYy x SsYy or SSyy x ssyy or ssyy x ssyy l. Dihybrid cross, AaBb x AaBb, what fraction of offspring will be homozygous for both recessive traits? m. Following a SsYy x SsYy cross, what fraction of the offspring are predicted to have a genotype that is heterozygous for both characteristics? n. In a dihybrid cross, SsYy x SsYy, what fraction of the offspring will be homozygous for both traits? o. Hemophilia in humans is due to an X-chromosome mutation. What will be the results of mating between a normal (non-carrier) female and a hemophiliac male? p. A female "carrier" who is heterozygous for the recessive, sex-linked trait causing red-green color blindness has child with normal male. What proportion of their sons will have color blindness?

5 q. A human female "carrier" who is heterozygous for the recessive, sex-linked trait red color blindness, marries a normal male. What proportion of their female progeny will show the trait? r. A rooster with gray feathers is mated with a hen of the same phenotype. Among their offspring, 15 chicks are gray, 6 are black, and 8 are white. What is the simplest explanation for the inheritance of these colors in chickens? What offspring would you predict from the mating of a gray rooster and a black hen? s. A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Extra digits is a dominant trait. What fraction of this couple's children would be expected to have extra digits? t. A woman has the rare (hypothetical) disease called bent fingers. She has children with a normal man, and all of their sons but none of their daughters have bent fingers. What is the mode of inheritance of bent fingers? a. Autosomal recessive b. Autosomal dominant c. X-linked recessive