Unit 6 Genetics and Herdity

Alleles

different variations of the same gene

Autosomal Dominant

common in the family, males and females are equally likely to inherit the disease, never skips a generation (a child can't inherit the disease if both parents are healthy)

Autosomal Recessive

most common inheritance pattern, rare in family, males and females are equally likely to inherit the disease, often skips generation

Autosomes

chromosomes 1-44 in a human

Blood Type

codominance (type AB is fully A and fully B) and multiple alleles (A, B, and i)

Carrier

someone who carries the recessive trait, but doesn't show it due to having a dominant X to mask it

Chromosome Mutation

often happen during meiosis, changing the number or location of genes

Chromosome Theory of Inheritance

genes are located on chromosomes and the behavior of chromosomes during meiosis accounts for inheritance patterns

Codominance

both traits are fully and seperately expressed

Cross

matching of two organisms

crossing a brown horse and a white horse create an appaloosa horese (white horse with brown spots)

What is an example of Codominance?

crossing red and white flowers make pink flowers

What is an example of incomplete dominance?

Dihybrid Cross

used when finding the possible genotypes for offspring when considering two traits at the same time

DNA

the macromolecule that has the instructions for making you who you are

Dominant

if present, allele will always have that trait expressed

Down Syndrome, Klinefelter's Syndrome, turner's sybdrome

What are examples of chromosome mutations?

Duplication

changes the size of chromosomes and results in multiple copies of a single gene

few genes

What does the Y chromosome contain?

Frameshift Mutations

the insertion or deletion of a nucleotide

Gene

section of DNA that provides the instructions for making a protein

Gene Mutation

happen during DNA replication and cause a change to the original DNA sequence

Genotype

the actual alleles inherited (FF, Ff, or ff)

Germ line mutation

occur in germ line cells that give rise to gametes and are passed on by meiosis creating a mutated offspring

Gregor Mendel

Austrian monk who used pea plants to learn about genetics, "father of genetics"

Heterozygous

two different alleles (Aa)

Homologous Chromosomes

the matching chromosomes from our mom and dad

Homozygous

two of the same alleles (AA or aa)

Incomplete Dominance

the heterozygous phenotype is somehwhere between the two homozygous phenotypes, neither allele is completely dominant or recessive

Law of Dominance

a dominant allele will express itself over a recessive allele

Law of Independent Assortment

the assortment of chromosomes for one trait doesn't affect the assortment of chromosomes for another trait

Law of Segrgation

when chromosomes seperate in meiosis, each gamete will receive only one chromosome from each pair

Linked Genes

genes that are physically located on the same chromosome will be inherited together

many genes that affect many traits

What does the X chromosome contain?

mistakes made during DNA replication, mitosis, meiosis, or ptotein synthesis

What causes mutations?

Monohybrid cross

a cross between two organisms looking at one trait

Multiple Alleles

having more than two alleles for one gene

Mutagens

chemical that can cause DNA mutations

Mutation

any change in DNA

Nondisjunction

chromosomes do not seperate correctly during anaphase, resulting in 1 or 3 chromosomes instead of two per cell

Pedigree

chart used to trace the phenotypes and genotypes in a family to determine whether people carry diseases or traits

Phenotype

the physical traits/characteristics seen in an organism (purple flowers)

Point Mutations

substitute one nucleotide for another

Polygenic Inheritance

A trait produced by two or more genes

protein

macromolecule that runs your body and expresses your traits

Punnett Square

a diagram that shows the probability of inheriting traits from parents with certain genes

Purebred

type of organism whose ancestors are genetically uniform

Recessive

allele will only have that trait expressed when the dominant allele is not present

Sex Linked Gene

gene located on a sex chromosome

Sex-Linked Recessive

rare in the family, males more often affected, often skips generations

Sex-Linked Traits

traits that are inherited with sex chromosomes, males have XY and females have XX, determine the biological sex of an individual

Somatic Mutations

occur in somatic cells and are passed on by mitosis and form cancer

Translocation

nonhomologous chromosomes exchange segments

X-Lined Genes

females inherit X-linked genes as normal and the principle of dominance applies since they have 2 X's so they inherit two copies of the gene