Chapter 9: Patterns of Inheritance Flashcards
Why did Gregor Mendel use pea plants
Easily observed characteristics
Short generation time
Fertilization can be controlled
What is p generation
Parental generation
What is the p generation
True breeding or pure bred parents
True breeding or purebred parents pass what
Their traits over and over again
F1 generation
Offspring of p generation
Mono hybrid cross
Mating between 2 organism which are similar in everything except 1 character
What is a dominant trait
A trait that shows up in every generation
Recessive trait
Trait that skips one or more generation
Alleles
For each character encoded by a gene, we have two versions
Homozygous dominant
Same two dominant alleles
Homozygous recessive
The same two recessive alleles
Heterozygous
One dominant and one recessive alleles
What are examples of genotype
Homozygous dominant, homozygous recessive, and heterozygous
What is a genotype
Genetic make up of organism tell us about genes or alleles
What is a phenotype
Phenotype tells us about physical features of an organism; something we can see or observe
Example of phenotype
Purple flowers and white flowers
In pea plants, 2 different ________, ___________ & __________ produce purple flowers, while ___________ produce white flowers
Genotypes, homozygous dominant and heterozygous, homozygous recessive
The Punnett square
Way to determine probably of seeing a particular trait in offspring
Phenotype ratio
Ratio between all physical features
Genotype ratio
A ratio between genetic make up
What is the difference between homologous and homozygous
Having the same allele at the same locus on both members of a pair of homologous chromosomes. Homozygous referees to a genotype consisting of two identical alleles of a gene
Traits encoded by genes that are located close to each other on a chromosome are more likely to do what?
Inherited together than those encoded by the genes far apart
How do we know if an animal is really a purebred?
Test cross
Test cross
Used to determine whether unknown genotype is homozygous dominant (pure bred) or heterozygous (mutt)
Wild type traits
Most often seen in nature and not necessarily specified by dominant allele
Example of wild type trait
Having no freckles, or normal pigmentation?
What are unique about autosomal disorders in humans (as far as alleles)
They can be dominant recessive
Pedigree
Shows the inheritance of a trait in a family through multiple generations
Example of pedigree
Family tree
When a shape is half shaded what does that mean
They are a carrier, heterozygous for recessive trait
Amiocentesis
Needle extracts amniotic fluid
What is amniotic fluid
Fluid that surrounds fetus
When does amniocentesis occur
Performed between 14-20 weeks of pregnancy
Chorionic Villus Sampling (CVS)
Suction tube extracts tissue from chorionic villi (growth found in placenta)
Which Karyotyping procedure is less invasive for fetus
CVS
When is chorionic villus sampling performed
8-12 weeks of pregnancy
When can you get the results of amniocentesis
Several weeks
When can you get the results of CVS
Several hours
Biochemical test analyze what
Gene products: enzymes and other proteins
Amniocentesis and CVS have in common?
Both can cause miscarriages
Genetic tests analyze what
DNA itself
In a cross between 2 heterozygous phenotypes and genotype ratios….
Are the same
Incomplete dominance
Heterozygous genotype has a phenotype that is intermediate between phenotypes of the two homozygotes
Why is incomplete dominance not truly dominant?
Because it can’t mask the recessive allele from being seen
What is an example of incomplete dominance in humans
LDL receptors
LDL: homozygous HH (dominant), does what? And what characteristics
Ability to make LDL receptors, normal concentration of cholesterol in blood
What is the genotype of normal cholesterol
HH
What is the genotype of someone with a mild disease of hypercholesteromia?
Hh, heterozygous
What is the phenotype of someone with mild disease of hypercholestermia?
1/2 of LDL receptors
What is the genotype of someone with high cholesterol
hh, homozygous
Pertaining to LDL, someone that is homozygous recessive has the ability to do what?
The inability to make LDL receptors
Can there be more than one dominant allele or a gene,
Yes, codominance
What is codominance
Two different alleles of a single gene are expressed and they don’t overpower each other in the phenotype
Example of codominance
AB blood type in humans
Gene that determines blood type in humans have how many different type of alleles
3 different types
What are the different types of alleles that determine blood
Ia, Ib, i
Which allele is dominant for blood
Ia and Ib, they codominate
What is pleiotrophy
Single gene affects several phenotypic characters
What is an example of pleiotrophy
Sickle cell anemia
Sickle cell anemia
Get abnormal hemnoglobin chrystallizes causing red blood cells tod become sickle shaped and get stuck in vessels and can’t deliver enough oxygen to organs…causing damage to other organs
In humans, what determines the sex of the baby?
The Y chromosome
