Chapter 3.1: Extension to Mendel for Single-Gene Inheritance Flashcards
Define multiple alleles
gene with more than 2 alleles
What is a gene with only one common, wild-type allele?
monomorphic
How many alleles does each of the 3 histocompatibility genes have?
Each of the 3 genes (HLA-A, HLA-B, HLA-C) has 400-1200 alleles
What determines whether 2 alternative alleles of a single gene show complete dominance, incomplete dominance, or codominance?
Whether 2 alternative alleles of a single gene show complete dominance, incomplete dominance, or codominance depends on the kinds of proteins determined by the alleles and the biochemical function of those proteins in the cell
What is a gene with more than 2 alleles?
multiple alleles
What is special about the Type AB blood type?
• Considered universal recipients, because they make neither anti-A nor anti-B antibodies, which if present, would target the surface molecules of incoming blood cells
What is the dominance series for lentil seed coat patterns?
Dominance Series: marbled-1 > marbled-2 > spotted = dotted > clear
What are the 5 alleles for lentil seed coats?
5 alleles: spotted, dotted, clear (pattern absent), and 2 types of marbled
What are traits determined by 2 or more genes?
multifactorial
Define codominant
trait shows up equally in the phenotype
What cause sickle-cell disease?
o Sickle-cell disease is the result of a faulty hemoglobin molecule
What are chance alternatives of the genetic material?
mutation
What are genes with more than one common allele?
polymorphic
Define mutation
chance alternatives of the genetic material
Define polymorphic
genes with more than one common allele
Define allele frequency
percentage of the total number of gene copies the allele accounts for
What type of antibodies does a Type AB blood type produce?
Type AB make neither antibody
What type of antibodies does a Type O blood type produce?
Type O produce both anti-A and anti-B antibodies
What is a trait is intermediate of parents?
incomplete dominance
What are the 3 alleles for ABO blood type?
The gene for the ABO blood types has 3 alleles: I^A, I^B, and i
What do the antibodies in blood do?
These antibodies cause coagulation of cells displaying foreign molecule
What is the most common allele in population; allele present in the population at a frequency greater than 1%?
wild-type allele (+)
What type of antibodies does a Type A blood type produce?
Type A produces anti-B antibodies
What type of antibodies does a Type B blood type produce?
Type B produces anti-A antibodies
Define wild-type alleles (+)
most common allele in population; allele present in the population at a frequency greater than 1%
What is the role of histocompatibility antigens in humans and where are they located?
Carried by all of the body’s cells except the red blood cells and sperm, histocompatibility antigens play a critical role in facilitating a proper immune response that destroys intruders while leaving the body’s own tissues intact
Relate sickle-cell disease to pleitropy
The Hbβ^S allele of the β-globin gene affects more than one trait
Define pleitropy
the phenomenon of a single gene determining a number of distinct and seemingly unrelated characteristics
What is special about the Type O blood type?
• Considered universal donors because their red blood cells carry no surface molecules that will stimulate an antibody attack in a transfusion recipient
What is the phenomenon of a single gene determining a number of distinct and seemingly unrelated characteristics?
pleiotropy
Define mutant allele
a rare allele in the population
Relate sickle cell disease to multiple alleles
The β-globin gene has a normal wild-type allele (Hbβ^A) that gives rise to fully functional β-globin, as well as 400 mutant alleles
What is trait shows up equally in the phenotype?
codominant
What is a rare allele in the population?
mutant allele
Define multifactorial
traits determined by 2 or more genes
Define incomplete dominance
trait is intermediate of parents
Define monomorphic
a gene with only one common, wild-type allele
What is an an allele that negatively affects the survival of a homozygote?
recessive lethal allele
Define common variants
high-frequency alleles of a polymorphic gene
Define recessive lethal allele
an allele that negatively affects the survival of a homozygote
What is the percentage of the total number of gene copies the allele accounts for?
allele frequency
What is the high-frequency alleles of a polymorphic gene?
common variants
