Patterns of Inheritance Flashcards
alleles that lead to the expression of the allele whether the individual is homo- or heterozygous for that gene
Autosomal Dominant Alleles
alleles that are only expressed when the individual is homozygous recessive for that gene
Autosomal Recessive Alleles
a family tree diagram that depicts the inheritance of a trait or disease through several generations
Pedigree
What can a Pedigree be used for?
To identify if a trait or disease is autosomal dominant or autosomal recessive
Autosomal disorders that do NOT skip generations
Autosomal Dominant Disorders
Autosomal disorders that skip generations
Autosomal Recessive Disorders
a characteristic pattern of inheritance exhibited by genes located on a sex chromosome
Sex Linkage
a non-Mendelian inheritance pattern that can give rise to a variety of phenotypes because of the gene interactions and interactions between genes and their environment
Multifactorial (Complex) Traits
a thread-like structure of tightly coiled DNA that contains part or all of an organism’s genetic material
Chromosome
any chromosomes that are not sex chromosomes
Autosomes
a pair of chromosomes that determine whether an organism is male or female
Sex Chromosomes
What sex chromosomes can males pass to offspring?
1 X or 1 Y
What sex chromosomes can females pass to their offspring?
1 of their 2 X’s
How many chromosomes do humans have? How many of those are autosomes vs sex chromosomes?
46 chromosomes
22 pairs of autosomes
1 pair of sex chromosomes
an organized profile of an organism’s chromosomes in the nucleus
Karyotype
the identical copies of each chromosome that are joined by the centromere
Sister Chromatids
where 2 sister chromatids are joined
Centromeres
an image of chromosomes arranged by size and other characteristics
Karyogram
What 2 things are karyograms used for?
- To create karyotypes
- To diagnose chromosomal aberrations
an organism with the appropriate number of chromosomes for the species
Euploid
an organism with more or less than the appropriate number of chromosomes for the species
Aneuploid
the process of disabling 1 of the 2 female X chromosomes to prevent females from having twice as many gene products from the X chromosome as males
X-Inactivation
inactivated X chromosomes
Barr Bodies
What 2 situations does X-inactivation occur?
- Only in females (typically)
- Early in embryonic development
Which female sex chromosome is deactivated?
1 of their sex chromosomes (Xs) are randomly deactivated
What is an example of X-inactivation?
Calico Cats
Pedigree Symbols:
square
male
Pedigree Symbols:
circle
female
Pedigree Symbols:
square + circle joined by lateral line
Mating Pair
Pedigree Symbols:
mating pair symbol connected by a vertical line to other symbols
Parents-Children
Pedigree Symbols:
any combo of circles and squares connected by an upward facing carat
Dizygotic (Non-Identical) Twins
Pedigree Symbols:
a triangle with 2 circles or squares
Monozygotic (Identical) Twins
Pedigree Symbol:
diamond
Unspecified Sex
Pedigree Symbol:
a number inside a circle or square
Number of Children
Pedigree Symbol:
shaded symbol
Affected Individuals
Pedigree Symbol:
half shaded symbol
Heterozygous for Autosomal Recessive Gene
Pedigree Symbol:
a dot in the center of a symbol
Carrier of a Sex-Linked Recessive Condition
Pedigree Symbol:
diagonal line through a symbol
Death
Pedigree Symbol:
shaded circle with a line from the top
Abortion or Stillbirth
Pedigree Symbol:
a shaded square with an arrow in the lower left
Propositus
the 1st identified individual who exhibits an inherited disease or disorder
Propositus
Pedigree Symbol:
a number outside a symbol
Where in the pedigree an individual occurs
Pedigree Symbol:
circle + square connected by 2 horizontal lines
Consanguineous Marriage (Blood-Related) Pairing
disorders in which people who have 1 or 2 copies of the recessive allele exhibit the disorder themselves since they do not have a dominant allele to mask it
Sex-Linked Recessive Disorders
disorders in which the people have 1 or 2 mutated alleles and exhibit the disorder themselves
Autosomal Dominant Disorders
Heterozygous individuals with an Autosomal Dominant Disorder > have a _____ chance of passing the mutated allele to each child
50%
Homozygous individuals with an Autosomal Dominant Disorder > have ____ chance of passing a mutated allele to each child
100%
Give an example of an autosomal dominant disorder
Huntington’s Disease
What scenarios cause daughters to exhibit sex-linked recessive disorders?
They must receive mutated alleles from BOTH parents or they will not exhibit the disorder
What kind of inheritance patterns can you see in Pedigrees for sex-linked recessive disorders?
They skip generations
Which chromosome passes on sex-linked recessive disorders?
Both - they can be passed on via the X or Y chromosome
If a mother exhibits a sex-linked recessive disorder, what conclusions can be drawn about her sex chromosomes?
Both her Xs are affected by the mutated allele
If a mother exhibits a sex-linked recessive disorder > ____ of her sons will inherit a mutated X chromosome
Why?
100%
The son won’t have another X chromosome to mask it
If a mother is a carrier for a sex-linked recessive disorder > each son has ____ chance of being affected.
Why?
50%
There is a 50% chance he inherits the unaffected chromosome
If a mother is a carrier for a sex-linked recessive disorder, what conclusions can be drawn about her sex chromosomes and her gene expression?
Only 1 of her 2 Xs are affected by the mutated allele
She does not exhibit the disorder, but her offspring might
family members with only 1 copy of the mutated recessive allele for a given gene that don’t display the trait themselves but can pass it to offspring
Carriers
Give an example of sex-linked recessive disorders
Red-green colorblindness
a genomic sequencing method used to determine the genetic sequences of long strands of DNA
Shotgun Sequencing
What are the 3 steps to Shotgun Sequencing?
- DNA is randomly broken up into many small fragments
- Each fragment is sequenced
- A computer program reassembles the DNA fragments
the science of collecting and analyzing complex biological data
Bioinformatics
the rearrangement and exchange of genetic information from different sources
Genetic Recombination
choosing to breed organisms that will result in offspring with desired characteristics
Selective Breeding
a type of selective breeding that occurs when individuals with similar characteristics continue to be bred to keep a certain set of traits
Inbreeding
organisms that have both their original DNA and the genes of other organisms, have certain genes deleted, or have already present genes manipulated
Transgenic Organisms
a rare genetic pattern in which a genetic mutation causes a single fertilized egg results in an individual with 2 different genomes
Mosaicism
a way for individuals to find out more about their individual genetic makeup and can diagnose many disorders
Genetic Testing
