Incomplete Dominance

A man with a Widow’s Peak and a woman with a Widow’s peak have only children who have Widow’s peaks. In another case, two people with Widow’s peaks have some offspring who have no Widow’s Peak. Is this possible? Why or why not? • What are the genotypes of the first set of parents? • What are the genotypes of the second set of parents?

A man with a Widow’s Peak and a woman with a Widow’s peak have only children who have Widow’s peaks. In another case, two people with Widow’s peaks have some offspring who have no Widow’s Peak. Is this possible? Why or why not? • What are the genotypes of the first set of parents? • WW/WW or WW/Ww • What are the genotypes of the second set of parents? • Ww/Ww

Incomplete Dominance • A red rose (RR) is bred with a white rose (KK). Neither red nor white is dominant nor recessive. What color will their offspring be?

Incomplete Dominance • A red rose (RR) is bred with a white rose (KK). Neither red nor white is dominant nor recessive. What color will their offspring be? 100% pink roses

Autosomal Recessive Disorders • Albinism is an autosomal recessive disorder. If you cross 2 heterozygous individuals, what percent of their offspring will be albino?

Autosomal Recessive Disorders • Albinism is an autosomal recessive disorder. If you cross 2 heterozygous individuals, what percent of their offspring will be albino? 25% albino offspring

Autosomal Recessive Disorders • Cystic Fibrosis is a lethal autosomal recessive disorder. What is the probability a child will have Cystic Fibrosis if one parent is heterozygous for the disorder (a carrier) and the other parent is homozygous dominant? • If two parents are both heterozygous for CF, what is the ratio of offspring without CF to offspring with CF?

Autosomal Recessive Disorders • Cystic Fibrosis is a lethal autosomal recessive disorder. What is the probability a child will have Cystic Fibrosis if one parent is heterozygous for the disorder (a carrier) and the other parent is homozygous dominant? • 0% chance CF offspring • If two parents are both heterozygous for CF, what is the ratio of offspring without CF to offspring with CF? • 3:1

Autosomal Dominant Disorder • Huntington’s Disease is an autosomal dominant disorder. What is the probability a child will have Huntington’s disease if his father is heterozygous for the disorder, but his mother is homozygous recessive? • What does that tell us about Dad?

Autosomal Dominant Disorder • Huntington’s Disease is an autosomal dominant disorder. What is the probability a child will have Huntington’s disease if his father is heterozygous for the disorder, but his mother is homozygous recessive? • 50% chance of offspring with HD • What does that tell us about Dad? • He has HD

X-linked Traits • Colorblindness is an X-linked recessive trait in humans. What is the probability that a girl will be colorblind if her father is not Colorblind (XNY)and her mother is a carrier(XNXn)?

X-linked Traits Colorblindness is an X-linked recessive trait in humans. What is the probability that a girl will be colorblind if her father is not Colorblind (XNY)and her mother is a carrier(XNXn)? 0% chance of CB female offspring

X-linked Traits • What is the probability that a boy would be color blind if his father and mother were both colorblind? • What is the probability that a girl would be color blind if her father is color blind, but her mother is not (two choices)?

X-linked Traits • What is the probability that a boy would be color blind if his father and mother were both colorblind? • 100% CB male offspring • What is the probability that a girl would be color blind if her father is color blind, but her mother is not (two choices)? • If mother is heteroz:50% chance of CB female offspring • If mother is homo dom: 0% chance of CB female offspring

Find the genotypes for all individuals below. You may need to complete Punnett Square(s) to prove your answer. Based on the genotypes, does this pedigree show an autosomal dominant trait, autosomal recessive trait, or a sex-linked trait or not enough information? DOMINANT RECESSIVE SEX-LINKED

Find the genotypes for all individuals below. You may need to complete Punnett Square(s) to prove your answer. Based on the genotypes, does this pedigree show an autosomal dominant trait, autosomal recessive trait, or a sex-linked trait or not enough information? DOMINANT RECESSIVE SEX-LINKED Not enough information…

Find the genotypes for all individuals below. You may need to complete Punnett Square(s) to prove your answer. Based on the genotypes, does this pedigree show an autosomal dominant trait, autosomal recessive trait, or a sex-linked trait or not enough information? DOMINANT RECESSIVE SEX-LINKED

Find the genotypes for all individuals below. You may need to complete Punnett Square(s) to prove your answer. Based on the genotypes, does this pedigree show an autosomal dominant trait, autosomal recessive trait, or a sex-linked trait or not enough information? DOMINANT RECESSIVE SEX-LINKED Not enough information…

WHITE BOARD PRACTICE PROBLEMS In guinea pigs, the allele for black fur is dominant to the allele for white fur. If two guinea pigs that are both heterozygous are mated, what is the probability that an offspring will be white?

WHITE BOARD PRACTICE PROBLEMS In guinea pigs, the allele for black fur is dominant to the allele for white fur. If two guinea pigs that are both heterozygous are mated, what is the probability that an offspring will be white? 25% White guinea pigs

In peas, green leaves (G) are dominant to white leaves (g). A genetic cross is made between a heterozygous dominant (Gg) male plant and a homozygous recessive (gg) female plant and 200 seeds are produced. How many of the seeds would you expect to result in plants with green leaves?

In peas, green leaves (G) are dominant to white leaves (g). A genetic cross is made between a heterozygous dominant (Gg) male plant and a homozygous recessive (gg) female plant and 200 seeds are produced. How many of the seeds would you expect to result in plants with green leaves? 100 green leaves

Colorblindness is a genetic disorder that affects 100% of children born to colorblind parents, and generally affects many more males than females. The inheritance pattern for colorblindness is BEST described as __________. • Dominant • Recessive • Sex-linked • Not enough info

A group of 4,000 people are surveyed for natural hair type, which usually shows an incomplete dominant inheritance pattern. They are asked if their hair is naturally straight, curly, or wavy. The results of the survey are shown in the table below. Based on the data in the table, approximately what proportion (fraction) of people in the study have curly hair?

A group of 4,000 people are surveyed for natural hair type, which usually shows an incomplete dominant inheritance pattern. They are asked if their hair is naturally straight, curly, or wavy. The results of the survey are shown in the table below. Based on the data in the table, approximately what proportion (fraction) of people in the study have curly hair? 991/4000 Approx: 1/4

Cystic Fibrosis is a genetic disease that affects mucus cells in the lungs. The disease affects only those individuals that have a homozygous recessive genotype (ff). A Punnett Square for a cross between two individuals that are heterozygous carriers for the disease is shown below. If the couple decides to have children, what is the predicted phenotypic ratio of normal children to children with Cystic Fibrosis?

Cystic Fibrosis is a genetic disease that affects mucus cells in the lungs. The disease affects only those individuals that have a homozygous recessive genotype (ff). A Punnett Square for a cross between two individuals that are heterozygous carriers for the disease is shown below. If the couple decides to have children, what is the predicted phenotypic ratio of normal children to children with Cystic Fibrosis? 3:1

Huntington's disease is a genetic disease caused by an autosomal dominant allele, meaning that anyone with a homozygous dominant (HH) or heterozygous (Hh) genotype has the disease. Researchers studying people with a family history of Huntington's conduct genetic tests to determine genotypes and record the results in the table below. Based on the data in the table, approximately what proportion of people in the study have Huntington's disease?

Huntington's disease is a genetic disease caused by an autosomal dominant allele, meaning that anyone with a homozygous dominant (HH) or heterozygous (Hh) genotype has the disease. Researchers studying people with a family history of Huntington's conduct genetic tests to determine genotypes and record the results in the table below. Based on the data in the table, approximately what proportion of people in the study have Huntington's disease? 320/412 Approx: 3/4

The Punnett Square above shows the possible allele combinations in the offspring of a human male with male–pattern baldness. Male–pattern baldness is an X–linked trait, and is represented by an Xb in the Punnett Square below. However, the allele combinations in the offspring in the Punnett square are not reasonable because

The Punnett Square above shows the possible allele combinations in the offspring of a human male with male–pattern baldness. Male–pattern baldness is an X–linked trait, and is represented by an Xb in the Punnett Square below. However, the allele combinations in the offspring in the Punnett square are not reasonable because Crossing two men!

Huntington's Disease is an autosomal dominant trait in humans. Which of the following pedigrees does NOT represent a possible inheritance pattern for Huntington's Disease?

Huntington's Disease is an autosomal dominant trait in humans. Which of the following pedigrees does NOT represent a possible inheritance pattern for Huntington's Disease? Can’t get dominant traits in offspring of homozygous recessive parents

If the pedigree below shows a genetic disease with a simple recessive inheritance pattern (qq), what are the genotypes of individuals III–3 and III–4?

If the pedigree below shows a genetic disease with a simple recessive inheritance pattern (qq), what are the genotypes of individuals III–3 and III–4? Qq and Qq Why? They have two homozygous recessive offspring

If the pedigree below shows the inheritance pattern of an X–linked trait, what is the chance that individual II–5 is a carrier?

If the pedigree below shows the inheritance pattern of an X–linked trait, what is the chance that individual II–5 is a carrier? • 100% chance that II-5 is a carrier • Why? • She has a homozygous recessive offspring

Incomplete Dominance