Genetics Answers

Using a worked example show how would you determine if a tall plant was

heterozygous or homozygous tall. Illustrate your answer with appropriate

crosses.

(d) Explain the concept of ‘multiple alleles’. Use the ABO blood grouping system to illustrate your answer. Produce a table to illustrate all possible phenotypes and their respective genotypes.

(It is not sufficient to copy and paste a table from a website)

From the sequence of RNA -C, U, A, C, A- what would you expect the complement strand of DNA to be?

In certain rose plants, white roses and red roses are incompletely dominant to one another. When a red rose is crossed with a white rose, a pink rose will result. What is the probability of producing more pink roses from two pink parents?

Achondroplasia, a form of Hereditary Dwarfism ( 10 points)

Achondroplasia is a hereditary constitutional bone disorder; it is the most common type of dwarfism, in which the child’s arms and legs are short in proportion to body length and have a characteristic face . This disease is caused by a mutation of the fibroblast growth factor receptor-3 gene (FGFR3) on human chromosome 4.

 Document 1 : A pedigree of a family whose certain members are affected by Achondroplasia.

1- Indicate if the allele responsible for the disease is dominant or recessive. Justify the answer.

2- Determine the chromosomal localization of the gene responsible for Achondroplasia .

3- Specify the genotype of each of the individuals (I-1), (III-9), and (IV- 4).

Homozygous fetuses that possess two copies of the mutant gene are not viable, and pregnancy is naturally interrupted.

4- Determine the risk for the couple III- 9 and III- 10 to have a third child affected by Achondroplasia.

In dragons, black body color is dominant to green body color. Cross one homozygous dominant dragon with one homozygous recessive dragon.

What are the genotypes of the parents

Using mainly labelled diagrams, (and some explanation) describe the sequence of events in the process of Meiosis in eukaryotic cells.

Indicate clearly where the opportunities arise in meiosis for genetic variation and outline and illustrate briefly how this happens

Explain the terms Chromosome, Chromatid, Gene, Allele.

(Use genetic notation (symbols for alleles) and annotated diagrams to illustrate your response. Show links between the terms)

2. Using mainly labelled diagrams, (and some explanation) describe the sequence of events in the process of Meiosis in eukaryotic cells.

Indicate clearly where the opportunities arise in meiosis for genetic variation and outline and illustrate briefly how this happens.

Create and illustrate an imaginary organism

And fill up this table below by Traits Exhibited by Imaginary Organism

Hypothetical Gene = Hypothetical Trait

A =

B =

C =

D =

E =

F =

List of Hypothetical Traits

Amino Acid Sequence= Traits

Cys-Tyr-Met-Cys-Asn= Straight hair

Cys-Tyr-Met-Leu-Asn= Curly hair

Cys-Asn-Gly-Thr-Phe= Red hair

Cys-Asn-Gly-Thr-His= Green hair

Thr-Pro-Arg-Ser-Phe-Phe= Tall

Thr-Pro-Arg-Tyr-Phe-Tyr= Short

Ala-Glu-Tyr= Big eyes

Ala-Glu-Leu= Small eyes

Ile-Leu-IIe-Cys-Trp= Long tail 

IIe-Leu-Cys-Trp-Thr= Short tail

Asn-Cys-Met-Leu-Cys= Brown skin

Asn-Cys-Met-IIe-Val= Yellow skin

Ser-Arg-Trp-Cys= Male

Ser-Pro-Leu-Cys= Female

DNA (leading strand): 5’ ATTTTAATATGTTGG  3’

DNA (lagging strand):    

mRNA:  

tRNA: 

Amino acid sequence:   

Trait: 

List of Hypothetical Traits

Amino Acid Sequence= Traits

Cys-Tyr-Met-Cys-Asn= Straight hair

Cys-Tyr-Met-Leu-Asn= Curly hair

Cys-Asn-Gly-Thr-Phe= Red hair

Cys-Asn-Gly-Thr-His= Green hair

Thr-Pro-Arg-Ser-Phe-Phe= Tall

Thr-Pro-Arg-Tyr-Phe-Tyr= Short

Ala-Glu-Tyr= Big eyes

Ala-Glu-Leu= Small eyes

Ile-Leu-IIe-Cys-Trp= Long tail 

IIe-Leu-Cys-Trp-Thr= Short tail

Asn-Cys-Met-Leu-Cys= Brown skin

Asn-Cys-Met-IIe-Val= Yellow skin

Ser-Arg-Trp-Cys= Male

Ser-Pro-Leu-Cys= Female

DNA (leading strand): 5’ TGTTACATGCTAAAT 3’

DNA (lagging strand):    

mRNA:  

tRNA: 

Amino acid sequence:   

Trait: