Mendelian Genetics Flashcards
What is the main difference between single-gene Mendelian traits and complex traits?
The number of genetic factors involved in their inheritance.
Simple Mendelian traits result from one genetic factor, while complex traits arise from multiple genetic risk factors.
What does transmission genetics encompass?
The basic principles of genetics and how traits are passed from one generation to the next.
It contrasts with molecular genetics, which deals with the chemical nature of genes.
What is the focus of molecular genetics?
The chemical nature of the gene itself: how genetic information is encoded, replicated, and expressed.
What organism did Mendel use for his experiments?
Common garden pea.
Mendel conducted his studies from 1856 to 1863.
What was Mendel’s goal in his experiments?
To determine the number of different forms in which hybrid progeny appear and ascertain their numerical interrelationships.
How do pea plants normally reproduce?
By self-fertilization, where pollen from the same flower fertilizes its own eggs.
What is true breeding?
Varieties that produce only progeny like themselves when allowed to self-fertilize.
What are examples of traits Mendel studied in pea plants?
- Seed shape (round vs. wrinkled)
- Seed color (yellow vs. green)
- Flower color (purple vs. white)
- Pod shape (smooth vs. constricted)
- Pod color (green vs. yellow)
- Flower and pod position (axial vs. terminal)
- Stem length (standard vs. dwarf)
What is the wildtype form of a trait?
The most common form occurring in a natural population, such as the round pea.
What are alleles?
Different forms of a particular gene, such as W and w.
What is the observed ratio of visible traits in the F generation of a monohybrid cross?
3:1 ratio of dominant to recessive traits.
What is the underlying ratio of genetic types in the F generation of a monohybrid cross?
1:2:1 ratio of WW, Ww, and ww.
What is a genotype?
The genetic constitution of an organism or cell, such as WW, Ww, or ww.
What does it mean if a genotype is heterozygous?
The members of a pair of alleles are different.
What does it mean if a genotype is homozygous?
The members of a pair of alleles are alike.
What is the phenotype?
The observable properties of an organism, including its visible traits.
What are the two possible genotypes for round seeds?
WW and Ww.
What is the addition rule in probability?
Prob (A or B) = Prob (A) + Prob (B).
What is the probability of an individual seed being round in a monohybrid cross?
3/4.
What are male-specific genes on the Y chromosome?
About 60 genes expressed specifically in the testis.
What is the significance of synonymous codons?
They represent chemically similar amino acids and minimize the effects of mutation.
How many triplet codons encode amino acids?
61 of the 64 possible triplets.
What is the wobble hypothesis?
Multiple codons that encode the same amino acid often differ at the third base position.
