FYSM 1310 Lecture Notes - Lecture 6: Zygosity, Phenotype, Amyloid

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purpleraven774

2 Feb 2017

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Alleles: variants of a gene that exists in a population. Genotype: an individual"s genetic structure, which alleles of a gene you carry. We each carry 2 copies of each gene (one from each parent) Homozygote: both copies of the gene are the same. Heterozygote: 2 different copies of the gene are the same. Heterozygote (brown eyes) homozygote (brown eyes) homozygote (blue eyes) Recessive: individuals who carry the recessive carrier gene have a. 50% chance of passing it on to their children. Familial alzheimer"s: usually inherited in autosomal dominant, fully penetrant patterns. Usually early onset (mom affected, dad not) only accounts for 5% of ad cases. Sporadic alzheimer"s: usually runs in families with no clear pattern. No single gene that causes the disease, instead there is a multiple susceptibility gene. The only established genetic risk factor for sporadic ad is apolipoprotein e.

Related Questions

1. A person is described as a carrier for a particular genetic disease. What does this tell you about their genotype?

2. For any given gene, the principle of independent segregation predicts that each gamete produced as a result of meiosis will contain ____________________

3. A pair of alleles is said to be heterozygous when:

4. In a diploid species, cells can have up to ___ alleles of a particular gene.

5. In a cross between a homozygous dominant parent and a homozygous recessive parent, the number of phenotypic classes observed in the offspring is ______

6. For a person of genotype Xx, the genotype of their gametes may be ______________

7. In a "test cross", an individual of unknown genotype is crossed with a ___ individual to determine the unknown genotype.

8. An albino woman has a child with a phenotypically normal man with no family history of albinism (which is a rare recessive disorder). What percentage of their children are likely to be albino?

9. An individual with the dominant phenotype, but an unknown genotype, is test-crossed, and all of the offspring exhibit the dominant phenotype. The genotype of the unknown individual is ______________

10. If two heterozygous individuals for a recessive disease (carriers) have a child, what is the chance that their child will develop the disease?

11. In a monohybrid cross between two true-breeding parents that both exhibit the dominant phenotype, ___ percent of the offspring will exhibit the recessive phenotype.

12. In a particular type of tomato plant, red fruit is dominant over yellow fruit, and dwarf height is a recessive trait. If two heterozygous plants were crossed, what proportion of the offspring would show the dominant phenotype?

13. In a cross between a BbRr individual and a BBRR one, what do the following represent: BR, Br, bR, br?

14. In humans, the gene that determines whether an embryo develops as a male or a female is carried on _____________

amaranthhare726

1. In the fruit fly, Drosophila melanogaster, the normal wildtype has long wings and red eyes (both are dominant traits).Recessive forms of these genes result in vestigial wings and browneyes. A red-eyed, vesigial winged male is crossed with abrown-eyed, long winged female.

(a) Assuming each parent is homozygous for the dominant alleles,write out the cross and give the genotype and phenotype of theoffspring.

(b) If each parent is a heterozygote for the dominant alleles,what are the genotypes, phenotypes and ratios of the potentialoffspring?

2. In peas, the allele for tall plant (T) is dominant to theallele for short plants and the allele for purple flowers (P) isdominant to white flowers (p). Write out the results of thefollowing crosses and determine the phenotypic ratios for each:

(a) TtPp x TtPp

(b) Ttpp x ttpp

(d) TTpp x ttPP

burgundytiger789

A three point cross was performed using fruit flies. The three loci are physically linked on the same autosome. The d allele, in the homozygous state, results in the recessive âdouble dorsalâ phenotype. Similarly, the r allele results in the recessive âround earsâ phenotype and the e allele in the recessive âendless eyeâ phenotype. In contrast, the D, R, and E alleles encode for the dominant wild type phenotypes at each of these loci.

True breeding (homozygous) flies were crossed to produce F1 offspring. Due to poor book-keeping, the genotypes of the parent flies were not recorded â but one parent fly had one mutant phenotype, while the other parent had the other two mutant phenotypes.

Phenotype Number of F2 Flies

Ears Dorsal Eyes

1) Round ears Double Dorsal Endless Eyes 230

2) Wild-type Wild-type Wild-type 260

3) Round ears Wild-type Wild-type 4,390

4) Wild-type Double Dorsal Endless Eyes 4,100

5) Round ears Double Dorsal Wild-type 15

6) Wild-type Wild-type Endless Eyes 15

7) Round ears Wild-type Endless Eyes 510

8) Wild-type Double Dorsal Wild-type 480

10,000 total

a) What is the phenotype of the F1 flies?

b) What is the genotype of the F1 flies? Your answer should indicate the phase of linkage.

c) What are the genotypes and phenotypes of the original parent flies (previously not recorded)? Your answer should indicate the phase of linkage.

d) Calculate the map distance in cM between each of the three loci and determine the gene order. Show all work for full credit. (6 points)

FYSM 1310 Lecture Notes - Lecture 6: Zygosity, Phenotype, Amyloid

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