Evolutionary Gentetics Flashcards
What is a gene?
A segment of DNA involved in producing a polypeptide chain. It can include regions that don’t code for amino acids and is a unit of heredity.
What are alleles?
One of a series of alternative forms of a gene that occupy the same locus on a particular chromosome and control the same character.
Who is considered the father of genetics?
Johann Gregor Mendel (1822-84) studied inheritance in peas in a quantitative way.
What was Mendel’s approach to studying inheritance?
He crossed peas with distinct characters, recorded, and analyzed results mathematically.
What were Mendel’s hypotheses regarding traits?
He questioned whether traits blend or are discrete heritable units.
What materials did Mendel use in his experiments?
Pea plants with distinct characters.
What method did Mendel use to prevent self-fertilization?
He removed the stamen (pollen producing) while immature.
What were the results of Mendel’s first filial offspring (F1)?
All F1 offspring were purple.
What were the results of Mendel’s second filial offspring (F2)?
705 purple and 224 white.
What conclusion did Mendel draw about the white trait?
The white trait isn’t lost; it appears again in the F2 generation and is recessive.
What is Mendel’s first law of inheritance?
The law of segregation states that alternative versions of heritable factors account for variations in inherited characters.
What does Mendel’s second law state?
Independent assortment of genes during gamete formation.
What does it mean for pea plants to be diploid?
They have two copies of each heritable factor, potentially with alternative versions.
What is a locus?
The position of the gene on the chromosome.
What is the difference between homozygous and heterozygous?
Homozygous means having two identical alleles for a particular gene, while heterozygous means having two different alleles.
What causes genetic variation among individuals?
Differences in genes or other DNA segments.
What is the relationship between phenotype and genotype?
Phenotype is the observable traits of an organism, while genotype is the genetic constitution.
What is incomplete dominance?
A genetic situation where neither allele is completely dominant over the other.
What is codominance?
Both alleles contribute separately to the phenotype.
Do genetic traits always assort independently?
No, genes on the same chromosome can be linked, but recombination during meiosis can occur.
What is pleiotropy?
One gene affects several phenotypic characters.
What is epistasis?
The expression of a gene at one locus impacts a gene at a second locus.
What are quantitative characters?
Characters that vary along a continuum and are often influenced by multiple genes.
What are multifactorial traits?
Traits that are influenced by both genetic and environmental factors.
