Mendelian Inheritance and Complex Traits

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What is the main concept that underpins Mendel's basic principles of inheritance?

Particulate inheritance (correct)

Multiple alleles

Codominance

Incomplete dominance

What is the relationship between the genotype and phenotype of a heterozygote in a case of incomplete dominance?

The phenotype is a combination of both homozygotes

The phenotype is identical to one of the homozygotes

The phenotype is unpredictable

The phenotype is distinct from and often intermediate to the phenotype of either homozygote (correct)

What is an example of codominance in humans?

Flower colour in snapdragons

Roan coat colour in cattle

The MN blood group (correct)

The ABO blood group

What is the number of alleles that a diploid individual can carry for a particular gene?

Two (A) Signup and view all the answers

What is the term for a gene that affects multiple phenotypes?

Pleiotropy (C) Signup and view all the answers

What is the reason behind the F1 pink heterozygous phenotype in the snapdragon plant?

Incomplete dominance with a dosage effect (C) Signup and view all the answers

What is the genotype of individuals with normal stature in the context of pseudoachondroplasia?

d/d (A) Signup and view all the answers

What is the characteristic of codominance in a monogenic character?

Both phenotypes manifest separately (C) Signup and view all the answers

What is the expected outcome of an individual with the genotype D/D in the context of pseudoachondroplasia?

Lethal outcome during embryonic development (A) Signup and view all the answers

What is the frequency of the recessive allele in commercial cultivated varieties of pea plants?

100% (A) Signup and view all the answers

What is the function of the LM and LN alleles in the human MN blood group system?

They encode antigens expressed on the surface of red blood cells (B) Signup and view all the answers

What is the genotype of an individual with the MN blood group?

LM LN (B) Signup and view all the answers

What is the probability of an individual being homozygous recessive for a particular gene in a dihybrid cross?

0.25 (C) Signup and view all the answers

What is the genotype of an individual that expresses a phenotype resulting from incomplete dominance?

Heterozygous (A) Signup and view all the answers

Which of the following is an example of a dominant trait present at low frequencies in human populations?

Polydactyly (A) Signup and view all the answers

What is the difference between the M and N blood groups?

M has the M-type antigen, while N has the N-type antigen (A) Signup and view all the answers

What type of inheritance pattern does pseudoachondroplasia exhibit?

Autosomal dominant (D) Signup and view all the answers

What is the ratio of the amount of gene product in the CR and CW genotypes in the snapdragon plant?

2:1:1 (D) Signup and view all the answers

What is the name of the gene associated with pseudoachondroplasia?

COMP (A) Signup and view all the answers

What is the frequency of people that are recessive homozygotes for the polydactyly trait?

99.75% (D) Signup and view all the answers

What is the probability that Tom and Mary's first child will be affected by the condition, given that both Tom and Mary are carriers (Aa) for the condition?

1/8 (C) Signup and view all the answers

What is the term for the phenomenon where the alleles of one gene segregate independently of another gene’s alleles?

Law of Independent Assortment (C) Signup and view all the answers

What is the pattern of inheritance exhibited by brachydactyly, a Mendelian trait described in humans?

Autosomal dominant (A) Signup and view all the answers

What is the term for a gene that, when mutated, causes a single-gene disorder?

Disease-causing gene (A) Signup and view all the answers

What is the name of the geneticist who documented brachydactyly as the first Mendelian trait described in humans?

William Curtis Farabee (A) Signup and view all the answers

What is the reason for the difference in the expression of oculocutaneous albinism (OCA) between individuals of European and African ancestry?

The genetic background of African populations is more conducive to pigment production (C) Signup and view all the answers

What is the genotype of an individual who is a carrier of cystic fibrosis but does not exhibit the disease?

Heterozygous for the CFTR gene (D) Signup and view all the answers

What is the pattern of inheritance of Huntington's disease?

Autosomal dominant (C) Signup and view all the answers

What is the genotype of an individual who can taste phenylthiocarbamide (PTC)?

CC or CG (D) Signup and view all the answers

What is the underlying cause of sickle cell anaemia?

A mutation in the human beta globin gene (HBB) (D) Signup and view all the answers

What is the primary mechanism by which the R allele of the pea shape gene (SBE1) influences the seed shape phenotype?

It codes for an enzyme that converts unbranched starch (amylose) to branched starch (amylopectin) (D) Signup and view all the answers

What is the significance of the heterozygous genotype (Rr) in the context of Mendel's pea plant breeding experiments?

It displays the dominant round seed phenotype (D) Signup and view all the answers

What is the relationship between the genotype and phenotype in the context of complete dominance?

The phenotype is determined by the dominant allele, regardless of the genotype (C) Signup and view all the answers

What is the practical application of understanding the genotype–phenotype relationship in the context of genetic counselling?

Predicting the likelihood of a genetic disease in offspring (B) Signup and view all the answers

What is the primary advantage of using the concept of dominance and recessivity in understanding the molecular mechanisms of disease?

It provides a framework for understanding the biochemical basis of disease (D) Signup and view all the answers

What is the role of the starch branching enzyme 1 (Sbe1) in the context of the pea shape gene (SBE1)?

It converts unbranched starch (amylose) to branched starch (amylopectin) (D) Signup and view all the answers

What is the significance of the concept of complete dominance in the context of Mendel's laws?

It is a fundamental principle that underlies the laws of inheritance (B) Signup and view all the answers

What is the primary goal of structure–function studies of proteins in the context of genetics and biotechnology?

To understand the biochemical mechanisms underlying a genetic trait (B) Signup and view all the answers

What is the significance of the R allele in the context of the pea shape gene (SBE1)?

It is responsible for the round seed shape phenotype (B) Signup and view all the answers

What is the primary application of understanding the genotype–phenotype relationship in the context of selective breeding?

Selecting for desirable traits in breeding programs (C) Signup and view all the answers