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Pattern Of Inheritance. Review. Define the Following. Gene Alleles Locus Homozygous Heterozygous Dominant Recessive Phenotype Genotype Monohybrid cros. Definition.
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Pattern Of Inheritance Review
Define the Following • Gene • Alleles • Locus • Homozygous • Heterozygous • Dominant • Recessive • Phenotype • Genotype • Monohybrid cros
Definition • A. gene - the unit of heredity; a section of DNA sequence encoding a single proteinB. alleles - two genes that occupy the same position on homologous chromosomes and cover the same traitC. locus - a fixed location on a strand of DNA where a gene or one of its alleles is locatedD. homozygous - having identical genes (one from each parent) for a particular characteristicE. heterozygous - having two different genes for a particular characteristicF. dominant - the trait that appears in the heterozygous condition G. recessive - the trait that is masked in the heterozygous condition H. phenotype - appearanceI. genotype - genetic makeupJ. monohybrid cross - cross involving a single pair of genes, one trait
Useful Links • http://www.life.umd.edu/classroom/bsci124/lec10.html
Which of the following is a heterozygous genotype? (1 point) • a) HHbb • B) HH • C) Hh • D) hh
- • If black hair (B) is completely dominant over brown hair (b), which of the following will produce brown hair? (1 point)A) BB • B) Bb • C) bb • D) Both A and B
In a plant, the tall characteristic (T) is dominant over the short (t). In a monohybrid cross, two tall plants produce 3 tall and 1 short offspring. What are the genotypes of the parents? • (A) TT, tt • (B) TT, Tt • (C) Tt, Tt • (D) tt, tt
With incomplete dominance, when a red flowered plant is crossed with a white flowered plant, the offspring will be • (A) red • (B) pink • (C) white • (D) all of these
State the Laws of Mendel • The inheritance of one pair of factors (genes) is independent of the inheritance of the other pair. • Law of Independent assortment
The "father of genetics" is (1 point) • GregorMendel. • Isaac Newton. • Carl Sagan. • Charles Darwin.
Hint: Think of a test cross • Tongue rolling (the ability to roll your tongue) is a dominant trait in humans. A woman who CAN roll her tongue is married to a man who CANNOT roll his tongue. They have four children, only two of whom CAN roll their tongues. Which of the following describes the genotypes of the parents (woman x man)? (1 point) a) Rrx rr • B) RR x rr • C) Rr x RR • D) Rrx Rr
- • What are the chances of a child being homozygous recessive for a trait if both parents are heterozygous? (1 point) a) 25% • B) 50% • C) 75% • D) 100%
- • Which of the following crosses will only produce homozygous recessive offspring? (1 point) a) RRYY x RRYY • B) RRYY x rryy • C) RrYyx rryy • D) rryyx rryy
- • In leopard frogs, black spots (B) are dominant over brown spots (b). A homozygous recessive male frog mates with a heterozygous female frog. What percentage of the offspring will have black spots? (1 point) a) 0% • B) 25% • C) 50% • D) 100%
- • In Australian Shepherds (a breed of dog), black fur (FB) is codominant with white fur (FW). The heterozygous phenotype is spotted fur--both black and white. A homozygous male with black fur mates with a spotted female. What percentage of the offspring from this cross are expected to be white? (1 point) a) 0% • B) 25% • C) 50% • D) 75%
- • Which of the following correctly lists all of the possible gametes that could be produced by a parent with the genotype BbNn? (1 point) a) Bb, Nn • B) BN, Bn • C) BN, Bn, bb, nn • D) BN, Bn, bN, bn
Multiple alleles • A man with blood type O marries a woman with blood type A. All of there seven children have blood type A. What is the woman's most likely genotype? (1 point) a) IAIA B)IAIB c) IAi d) ii
- • In pea plants, round peas (R) are dominant over wrinkled peas (r). A cross between two plants yielded the following results: ROUND: 148WRINKLED: 51 • Based on this information, which of the following crosses represents the most likely genotypes of the parents? (1 point) a) RR x RR • b) RR x Rr • C) Rrx Rr • D) Rrx rr
- • The sex-linked allele for colorblindness is located on (1 point)a) chromosome 21. • B) the X chromosome only. • C) the Y chromosome only. • D) both the X chromosome and the Y chromosome.
- • Colorblindness is more common in males than in females because (1 point) a) fathers pass the allele for colorblindness to their sons only. • B) the allele for colorblindness is located on the Y chromosome. • C) males who are colorblind have two copies of the allele for colorblindness. • D) the allele for colorblindness is recessive and located on the X chromosome.
The genetic make up of an organism _________ • The physical characteristics of on organism _____
Practice Genetics Problems • Solve the genetics problems in the following slides based on the concepts of monohybrid cross, dihybrid cross, incomplete dominance, multiple alleles, sex-linked inheritance, autosomal dominant and recessive inheritance.
Genetic Problems • Most individuals of a certain wild flower have white petals, but a few are blue. Crosses have shown that the blue color is due to a recessive allele. Use "W" for white and "w" for blue. • a. What is the genotype of a blue-flowered plant and what gametes would it produce as a result of meiosis?d. If a blue-flowered plant is crossed with its white-flowered parent, what fraction of their offspring would have the genotype "ww"? • e. If two blue-flowered plants cross, what fraction of their offspring will be blue? White?
Incomplete Dominance • Four o'clocks exhibit incomplete dominance. Thus, if a plant with red flowers is crossed with a plant with white flowers, the offspring will all produce pink flowers. • What offspring would you expect if you crossed a red-flowered plant with a pink-flowered plant?
Dihybrid Cross • In peas, the gene for tall plants (T) is dominant over the gene for dwarf plants (t) and round seed (R) is dominant over wrinkled seed (r). If one crosses a homozygous tall, wrinkled-seeded plant with a homozygous dwarf, round-seeded plant, what is the phenotype of the F1? The genotype of the F1? The phenotypic ratio of the F2?