Lectures 10-11 Flashcards
What is genetics?
Study of heredity and variation of inherited characteristics
What is the blending of inheritance?
Offspring have traits that are a blend of parent’s traits
What did Mendel hypothesize about inheritance?
A ‘particulate’ unit of inheritance - genes
Define a gene.
Portion of DNA within a chromosome that contains info to specify/influence a trait
What does monogenic mean?
One gene governs a trait
What does polygenic mean?
Multiply genes govern a trait
What is a chromosome?
Unit of DNA that contains many genes
How many genes does chromosome 9 have?
800 genes
What are diploids?
2 homologs of each chromosome/2 of each gene (can be identical or not)
Define allele.
Each version of a gene
What does homozygous mean?
Allele on each chromosome is the same
What does heterozygous mean?
Allele on each chromosome is different
What is a genotype?
A set of alleles carried by an individual (e.g., Pp)
What is a phenotype?
Physical trait from a genotype (e.g., purple flower)
What are true-breeding organisms?
Organisms that always show a particular phenotype in every generation
What is the parental generation in genetics?
Parents in original cross (P0)
What is the first filial generation?
Offspring of parental generation (F1)
What is the second filial generation?
Offspring of F1 (F2)
What are monohybrid crosses?
Parents that are only different in 1 trait
What are dihybrid crosses?
Parents that are only different in 2 traits
In a monohybrid cross, what is the F2 generation’s genotypic ratio?
1:2:1
In a monohybrid cross, what is the F2 generation’s phenotypic ratio?
3:1
What is the Law of Segregation?
During meiosis, homologous chromosomes segregate during anaphase 1
What is required for simple Mendelian inheritance to occur?
Each trait is governed by a single gene
Fill in the blank: Incomplete dominance occurs when parents with 2 different phenotypes can produce offspring with a _______.
third phenotype
What is codominance?
Heterozygote will have both phenotypes
What are the blood types controlled by in humans?
3 alleles of ABO gene (or I gene)
What does the IA allele cause?
Pattern of glycosylation of RBCs - type A
What does the IB allele cause?
Different pattern of glycosylation of RBCs - type B
What does the Ii allele cause?
No pattern of glycosylation of RBCs - type O
What does the I gene code for?
An enzyme (a glycosyltransferase)
What is the result of the R allele in flower color genetics?
Makes higher anthocyanin production
What is the result of the W allele in flower color genetics?
Almost no anthocyanin production
