Introduction to Genetics

what did mendel conclude about the gametes?

an organism only donates one copy of each gene to their gametes

what does the law of independent assortment say?

when gametes are formed, alleles of a gene for one trait segragate independtly from alleles of a gene for another trait. (yellow pea pods do not always have yellow peas)

who was gregor mendel?

an austrian monk who worked with pea plants to show patterns of inheritance

punnett square example

if a child had this punnett square for eye color, the eye color have a 1:2:1 ratio for genotype and a 3:1

what is an example of a recessive allele?

if a mother has blonde hair, and the father has brown hair, the child will have brown hair because blone hair is a recessive trait

what is an example of a dominant allele?

if a mother has blonde hair, and the father has brown hair, the child will have brown hair because brown hair is a dominant trait

what did mendel specifically look for in the pea plants?

traits

what determines the phenotype?

genotype

what are the two things that a pairing of alleles can be described as?

homozygous or heterozygous

what are the three possibilities for a dominant and recessive allele group?

homozygous pair dominant: RR homozygous pair recessive: rr heterozygous pair dominant: Rr

what is a genotypic ratio?

how many allele combinations are there in a single punnett square?

what is a phenotypic ratio?

how many physical appearances are represented in the punnett square?

what is a cross

mating or two organisms to show their offspring

what is a purebred?

organism that is genetically uniform

what did mendel conclude about the inheritance of genes in his experiments?

organisms inherit two copies of each gene

what is a phenotype?

physical characteristics

what does the law of dominance say?

some alleles are dominant, some are recessive. the dominant alleles over shadow the recessive alleles so recessive alleles only appear in the offspring of two organisms if no dominant gene is present

what is a homozygous allele pair?

two identical forms of the alleles (both alleles are blonde hair color or both are brown hair color)

what is a genotype?

a person's genetic makeup of a set of genes

what are genes?

a peice of DNA that provide certain instructions to make a certain protien

what is a genome?

all of the organisms genetic material

what is a recessive trait?

allele that is expressed only when both alleles are recessive

what is a dominant allele?

allele that is expressed when present

what are alleles?

alternate forms of a gene

what does the law of segragation say?

each parent carries two alleles for each trait. during gamete formation, the two alleles are separated between the two gametes

what is gregor mendel know as?

the father of genetics

what is genetics?

the study of biological inheritance patterns and variation of organisms

what is a heterozygous allele pair?

their are two different forms of the allele (one allele is blonde hair and the other is brown hair color)

what did mendel conclude about traits in his experiments?

they are inherited as discrete units