Inheritance Flashcards
What is genotype?
Genetic makeup of individual
What is phenotype?
Visible characteristics of an individual
by proteins in the cytoplasm
What influences phenotype?
Genotype
What are the influences of both genotype and phenotype?
Environment
- radiation
- diet
How does radiation affect genotype?
Causes mutations
How many copies does each individual have of a gene?
Two copies
How many alleles does each individual have of a gene?
One alleles, both the same
or
two different alleles
How many alleles are there in a population?
Many different alleles
What does homozygous mean?
Two alleles of a gene are the same
What does heterozygous mean?
Two alleles of a gene are different
What does hemizygous mean?
Have only one allele of a gene
What are some examples of genes for which a male is hemizygous?
Genes on X chromosomes
What does dominant mean?
Allele that expresses itself regardless of other allele
What does recessive mean?
Allele that expresses itself only when it is present in both copies of gene
What does co-dominant mean?
Two different alleles are equally as dominant, expressed equally in phenotype
What is a classic example of a human co-dominant gene?
Human isoglutamin gene
What does the human isoglutamin gene code for?
Glycoproteins on surface of red blood cells
What are the three alleles of the human isoglutamin gene?
A
B
O
How are the alleles of the human isoglutamin gene expressed?
A and B are co-dominant
A is dominant over O
B is dominant over O
What are the different phenotypes of the human isoglutamin gene?
Blood group A
Blood group B
Blood group AB
Blood group O
What are the possible genotypes of blood group A phenotype?
A A
A O
What are the possible genotypes of blood group B phenotype?
B B
B O
What is the genotype of blood group AB phenotype?
A B
What is the genotype of blood group O phenotype?
O O
How are individuals in a pedigree numbered?
Generations by roman numerals
Individuals in a generation by normal numbers
What are the different types of inheritance patterns?
Autosomal/sex-linked
Recessive/dominant
Mitochondrial
Who is affected by autosomal recessive diseases?
Homozygous recessives
Are males or females affected by autosomal recessive diseases?
Both equally affected
What is the chance of two heterozygote parents having an affected offpsring with autosomal recessive diseases?
25% chance
What is the chance of two homozygous recessive parents having an affected offspring with autosomal recessive diseases?
100% chance
Who is affected by autosomal dominant diseases?
Heterozygous individuals
Are males or females affected by autosomal dominant diseases?
Both equally affected
What is the chance of a heteroygous individual having affected offspring with autosomal dominant diseases?
50% chance
Who is affected by X-linked recessive diseases?
Hemizygous recessive males
Homozygous recessive females
Are males or females affected by X-linked recessive diseases?
Males more commonly affected
What is the chance of a hemizygous recessive male having an affected son with X-linked recessive diseases? Why?
0% chance
males recieve their X chromosome from their mother
What is the chance of a heterozygous female having an affected son with X-linked recessive diseases?
50%
Who is affected by X-linked dominant diseases?
Hemizygous males
Heterozygous females
What is the chance of a hemizygous male having an affected daughter with X-linked dominant diseases? Why?
100%
daughters recieve one X chromosome from their father
What is the chance of a heterozygous female having an affected offspring with X-linked dominant diseases?
50% chance
Who is affected by Y-linked diseases?
Hemizygoys males
Are males or females affected by Y-linked diseases? Why?
Only males
only males have Y chromosome, females don’t
What is the chance of an affected father having an affected son with Y-linked diseases? Why?
100%
sons recieve their Y chromosome from their father
How are mitochondria inherited?
From mother to offspring
Are males or females affected by mitochondrial disease?
Both equally affected
What are the chances of an affected mother having affected offspring with mitochondrial disease?
100%
What are the chances of an affected father having affected offspring with mitochondrial disease?
0%
What does monogenic mean?
Only one gene involved in producing phenotype
What does polygenic mean?
Multiple genes involved in producing phenotype
What are linked genes?
Genes on same chromosome
What are not-linked genes?
Genes on different chromosomes
What are tightly linked genes?
Genes very close together on the same chromosome
How are linked genes affected by random assortment?
Don’t show random assortment
How are tightly linked genes affected by crossing over and recombination? Why?
Less likely to be separated by crossing over and recombination
because less space for chiasmata to form in between
same allele combinations inherited
How are genes far apart on the same chromosome affected by crossing over and recombination?
More likely to be separated by crossing over and recombination
because more space for chiasmata to form in between
different allele combinations inherited
