3.4 Inheritance

Distinguish between sex-linked genes and genes with linked loci.

Distinguish between sex-linked genes and genes with linked loci.

Distinguish between sex-linked genes and genes with linked loci.

Outline how it can be shown that the genes for shell base colour (Cc) and presence or absence of bands (Bb) are linked.

Nail patella syndrome is a rare disease that causes abnormalities of the nails and some bones. Its alleles are linked to the blood group alleles on the same chromosome. The pedigree chart shows the inheritance of these two characteristics over three generations.

[Source: Copyright © 1998. Phillip McClean]

Which descendant represents a recombinant phenotype?

Outline how it can be shown that the genes for shell base colour (Cc) and presence or absence of bands (Bb) are linked.

Outline how it can be shown that the genes for shell base colour (Cc) and presence or absence of bands (Bb) are linked.

The genes for cystic fibrosis and blood group are not linked. Two parents are heterozygous for cystic fibrosis. One parent has blood group O and the other has blood group AB. Using a Punnett square, determine the probability that their child will have both cystic fibrosis and blood group A.

The genes for cystic fibrosis and blood group are not linked. Two parents are heterozygous for cystic fibrosis. One parent has blood group O and the other has blood group AB. Using a Punnett square, determine the probability that their child will have both cystic fibrosis and blood group A.

The genes for cystic fibrosis and blood group are not linked. Two parents are heterozygous for cystic fibrosis. One parent has blood group O and the other has blood group AB. Using a Punnett square, determine the probability that their child will have both cystic fibrosis and blood group A.

Nail patella syndrome is a rare disease that causes abnormalities of the nails and some bones. Its alleles are linked to the blood group alleles on the same chromosome. The pedigree chart shows the inheritance of these two characteristics over three generations.

[Source: Copyright © 1998. Phillip McClean]

Which descendant represents a recombinant phenotype?

The pedigree chart shows a family affected by cystic fibrosis.

[Source: © International Baccalaureate Organization 2019]

What is the genotype of the affected boy’s father?

A. AA only

B. Either AA or Aa

C. Aa only

D. aa only

Creeper in chickens is a condition in which the chickens are born with very short legs. The creeper allele (C) is dominant over the normal allele (c). Embryos which are homozygous for the dominant allele fail to develop into viable chickens and die before they hatch. What phenotypic ratio would you expect in the live offspring of a cross between two creeper chickens?

A. All creeper

B. 1 creeper; 2 normal

C. 2 creeper; 1 normal

D. 3 creeper; 1 normal

The pedigree chart shows a family affected by cystic fibrosis.

[Source: © International Baccalaureate Organization 2019]

What is the genotype of the affected boy’s father?

A. AA only

B. Either AA or Aa

C. Aa only

D. aa only

Creeper in chickens is a condition in which the chickens are born with very short legs. The creeper allele (C) is dominant over the normal allele (c). Embryos which are homozygous for the dominant allele fail to develop into viable chickens and die before they hatch. What phenotypic ratio would you expect in the live offspring of a cross between two creeper chickens?

A. All creeper

B. 1 creeper; 2 normal

C. 2 creeper; 1 normal

D. 3 creeper; 1 normal

Which pedigree chart is consistent with the inheritance of red-green colour blindness?

[Source: © International Baccalaureate Organization 2019]

Which pedigree chart is consistent with the inheritance of red-green colour blindness?

[Source: © International Baccalaureate Organization 2019]

The pedigree chart shows the inheritance of hemophilia in some of the descendants of Queen Victoria. Which letter points to a family member certain to be heterozygous?

[Source: © International Baccalaureate Organization 2019]

The pedigree chart shows the inheritance of hemophilia in some of the descendants of Queen Victoria. Which letter points to a family member certain to be heterozygous?

[Source: © International Baccalaureate Organization 2019]

A pair of alleles controls the secretion of antigens corresponding to blood group in saliva. Examine the pedigree chart.

[Source: © International Baccalaureate Organization 2019]

Based on this pedigree chart, which best describes the allele conferring antigen secretion in saliva?

A. Dominant

B. Recessive

C. Sex-linked

D. Co-dominant

A pair of alleles controls the secretion of antigens corresponding to blood group in saliva. Examine the pedigree chart.

[Source: © International Baccalaureate Organization 2019]

Based on this pedigree chart, which best describes the allele conferring antigen secretion in saliva?

A. Dominant

B. Recessive

C. Sex-linked

D. Co-dominant

Outline the inheritance of blood types in the ABO blood system in humans.

Outline the inheritance of blood types in the ABO blood system in humans.

Outline the inheritance of blood types in the ABO blood system in humans.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Draw the symbol for individual X on the diagram.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

A couple have four children whose blood groups are A, B and AB. What is the likely combination of the parents’ genotypes?

A.  I^Ai and I^Bi

B.  I^Ai and I^BI^B

C.  I^AI^B and ii

D.  I^AI^A and I^BI^B

Draw the symbol for individual X on the diagram.

A couple have four children whose blood groups are A, B and AB. What is the likely combination of the parents’ genotypes?

A.  I^Ai and I^Bi

B.  I^Ai and I^BI^B

C.  I^AI^B and ii

D.  I^AI^A and I^BI^B

Draw the symbol for individual X on the diagram.

Calculate the probability of male Y having an allele for the disorder.

Calculate the probability of male Y having an allele for the disorder.

Calculate the probability of male Y having an allele for the disorder.

A total of 271 164 people were tested for blood groups in Mexico. The pie chart summarizes the ABO blood group distribution.

^{[Source: Canizalez-Román, A. et al., 2018. Blood Groups Distribution and Gene Diversity
of the ABO and Rh (D) Loci in the Mexican Population.
BioMed Research International, (Article ID 1925619).
http://dx.doi.org/10.1155/2018/1925619. Public domain.]}

What can be concluded from the ABO blood group distribution in Mexico?

A.  Allele frequencies are not the same for all blood group alleles.

B.  The majority of the Mexican population shows a co-dominant phenotype.

C.  Most of the Mexican population can receive blood from all blood groups.

D.  Only 2 % of the Mexican population have a heterozygous genotype for blood groups.

A total of 271 164 people were tested for blood groups in Mexico. The pie chart summarizes the ABO blood group distribution.

^{[Source: Canizalez-Román, A. et al., 2018. Blood Groups Distribution and Gene Diversity
of the ABO and Rh (D) Loci in the Mexican Population.
BioMed Research International, (Article ID 1925619).
http://dx.doi.org/10.1155/2018/1925619. Public domain.]}

What can be concluded from the ABO blood group distribution in Mexico?

A.  Allele frequencies are not the same for all blood group alleles.

B.  The majority of the Mexican population shows a co-dominant phenotype.

C.  Most of the Mexican population can receive blood from all blood groups.

D.  Only 2 % of the Mexican population have a heterozygous genotype for blood groups.

Explain the conclusion that can be drawn from Cross 1.

Explain the conclusion that can be drawn from Cross 1.

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

Explain the conclusion that can be drawn from Cross 1.

Explain the conclusion that can be drawn from Cross 1.

Explain the conclusion that can be drawn from Cross 1.

Explain the conclusion that can be drawn from Cross 1.

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

State how many chromosomes there would be in male or female gametes of L. purpureus.

State how many chromosomes there would be in male or female gametes of L. purpureus.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

State how many chromosomes there would be in male or female gametes of L. purpureus.

Outline the sequence of events that occurs during mitosis.

Outline the sequence of events that occurs during mitosis.

Outline the sequence of events that occurs during mitosis.