Working as a genetic counsellor, you have constructed a pedigree based on the family history of a genetic trait. Unless told otherwise in a question, you are to assume full penetrance of the trait based on the genotype. Individuals with the trait are coloured in blue, those without the trait are white. The dominant version of the allele is B, while the recessive version is b.

Based on your analysis of the pedigree, what is the most likely mode of inheritance:

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Given the most likely mode of inheritance, determine the genotype of the following individuals, using the following rules (answers are case sensitive):

• If autosomal use B (dominant) and b (recessive)

• If X-linked use XB (dominant), Xb (recessive) and Y

• If Y-linked use X, YB (affected) and Yb (unaffected)

• Dominant versions of the allele come before recessive ones (Bb NOT bB, XBXb NOT XbXB)

• If sex linked, X chromosomes come before Y chromosomes (XBY NOT YXB, XYb not YbX)

• No spaces should be placed between alleles.

Person B:

Person C:

Person D:

Person E:

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Person C and person D are looking to have another child. What is the chance:

They have a child with have the trait: 

% (enter a number only, e.g. 1 NOT one, do not include the percentage sign)

If they have a daughter, their daughter will have the trait: 

% (enter a number only, e.g. 1 NOT one, do not include the percentage sign)

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Previously you assumed 100% penetrance. If the people in the above pedigree had the same genotypes, however the trait instead had a penetrance of 25%, how many people with the trait would you expect in the pedigree?

people with the trait (enter a number only, e.g. 1 NOT one)

In a cross of AaBbCc x AaBbCc, what is the probability of producing an offspring with the genotype aabbcc?

Suppose a plant has two alleles for colour, green is dominant and yellow is recessive. If we cross a heterozygous plant with a yellow homozygous plant, what is the expected ratio of green:yellow plants in the F1 progeny?

A gene is located on the X chromosome and is recessive. Which sex would the phenotypic trait be displayed more often in?

In cows, heterozygotes are roan in colour, while homozygotes are either red or white. When crossing a roan and white cow, what proportion of the offspring will be roan in colour?

Mendel’s law of independent assortment states that:

Suppose a plant has two alleles for colour: green being dominant and yellow recessive. The plant also has two alleles for shape: round being dominant and wrinkled recessive.

If two plants heterozygous for each trait are crossed, what proportion of the offspring would you expect to be green and round?

During meiosis, crossing over occurs between homologous chromosomes. The recombinant chromosome will most likely contain the same alleles as the non-recombinant chromosome if the genes are:

Among a breed of sheep, black coat (B allele) colour is dominant to white (b allele). Curly hair (C allele) is dominant to straight hair (c allele). Assume classical mendelian inheritance. A true breeding male sheep with black and curly hair is crossed with a true breeding female with white and straight hair to produce an F1 generation.

This F1 generation will all have

A male offspring of this F1 generation is then mated with a female with the same genotype as its mother. Fill in the following punnett square using the alleles of the F1 father and the true breeding white and straight haired mother, using the flowing rules:

• Dominant versions of the allele come before recessive ones (Cc NOT cC)

•  B or b alleles come before C or c (BbCc, NOT CcBb AND NOT BCbc)

• Gametes should be ordered in table left to right, and top to bottom based on the above rules (i.e. Left/Top - BC - Bc - bC - bc - Right/Bottom, if applicable

• No spaces or symbols should be placed between alleles.

• Only enter the alleles into the able, do not enter anything else

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What is the chance of the mother and father in the punnett square producing offspring with:

Black and straight hair: 

% (enter a number only, e.g. 1 NOT one, do not include the percentage sign)

White and straight hair: 

% (enter a number only, e.g. 1 NOT one, do not include the percentage sign)

In the following table record the likelihood of producing a zygote with the various sex aneulploidies due to a single non-disjuction (ND) event.

Make sure your answer is recorded as a PERCENTAGE (fractions or decimal places are not permitted). 

You are to assume that meiosis continues in the other parent normally (i.e. there will be no double non-disjunctions).  Further, if a nondisjunction occurs during Meiosis I, you are to assume the Meiosis II continues normally and vice versa.

Make sure that your answer is only a number. Written words, punctuation marks or the inclusion of the percentage sign, will result in your answer being recorded incorrect.