Inheritance: basic laws and test cross Flashcards
It reflects the ACTIONS OF CHROMOSOMES and the genes they carry DURING MEIOSIS. A diploid individual possesses a pair of alleles for any particular trait and EACH PARENTS PASSES ONE of these randomly to its offspring.
Law of Segregation
It states that for TWO GENES on different chromosomes, the inheritance of one gene DOES NOT influence the chance of inheriting the other gene.
Law of Independent Assortment
These are the patterns in which SINGLE-GENE TRAITS and DISORDER OCCURS IN FAMILIES.
Modes of Inheritance
OFFSPRING has the SAME TRAIT as a parent.
True breeding
It carries the SAME ALLELES TT or tt.
Homozygous
It carries DIFFERENT ALLELES Tt.
Heterozygous
ORGANISM’S ALLELES.
Genotype
The outward EXPRESSION OF AN ALLELE combination.
Phenotype
Most COMMON PHENOTYPE.
Wild Type
The OBSERVED TRAIT is?
Dominant
The MASKED TRAIT is?
Recessive
Recessive traits are due to…
Loss of Function
Dominant traits are due to…
Gain of Function
Mendel’s laws can appear NOT TO OPERATE when ONE GENE masks or otherwise AFFECTS the PHENOTYPE OF ANOTHER.
Example: Bombay Phenotype
Epistasis
It refers to the PERCENTAGE OF INDIVIDUALS who have a PARTICULAR GENOTYPE have the associated phenotype.
Example: Polydactyly
Penetrance
It refers to VARIABILITY IN SEVERITY of a phenotype or the extent to which the gene is expressed.
Example: Polydactyly
Expressivity
A SINGLE-GENE DISEASE with many symptoms, or a gene that controls SEVERAL FUNCTIONS or HAS MORE THAN EFFECT.
Example: Marfan Syndrome
Pleiotropic
Mutations in DIFFERENT GENES produce the SAME PHENOTYPE.
Example: Osteogenesis Imperfecta
Genetic Heterogeneity
An environmentally CAUSED TRAIT that appears to be inherited.
Example: Infection
Phenocopy
Genetics refers to the TRANSMISSION OF GENES on the SAME CHROMOSOMES.
Linkage
What type of mutation is ALBINISM?
Autosomal Recessive Trait
What type of mutation is Polydactyly?
Autosomal Dominant Trait
These are SYMBOLIC REPRESENTATIONS of FAMILY RELATIONSHIPS and the TRANSMISSION OF INHERITED TRAITS.
Pedigree
A phenotypic class DOES NOT SURVIVE TO REPRODUCE.
Example: Achondroplasia
Lethal Alleles
MANY VARIANTS or DEGREES of a phenotype are possible.
Example: Cystic Fibrosis
Multiple Alleles
A heterozygote’s phenotype is INTERMEDIATE BETWEEN those of the TWO HOMOZYGOTES.
Example: Familial Hypercholesterolemia
Incomplete Dominance
A heterozygote’s phenotype is DISTINCT from and NOT INTERMEDIATE BETWEEN those of the TWO HOMOZYGOTS.
Example: ABO Blood Types
Codominance
