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Flashcards in Genetics Deck (18)
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1

Nondisjunction

Rare failure of the chromosomes to separate during any phase of meiosis; too many chromosomes in a gamete

2

Down Syndrome

Result of nondisjunction; has three instead of two of the #21 chromosome

3

Genotype

The genetic makeup of an organism (Aa)

4

Phenotype

An organisms physical appearance; not always and indication of the genotype

5

Homozygous

An organism that has inherited two matching alleles for a trait (AA)

6

Heterozygous

An organism has two different alleles for a trait (Aa)

7

Sex Linkage

Traits linked to sex; traits located on the X chromosome only

8

Gene

A heritable trait

9

Allele

Alternate versions of a gene (round nose, pointed nose)

10

Chromosome

Fibers that house the cells DNA; each section houses a particular gene

11

Pleiotropic Inheritance

One gene has the capacity to determine and influence multiple traits

12

Polygenic Inheritance

Two or more genes determine a single character

13

Multiple Alleles

Premise that most genes have more than two forms (not just dominant or recessive); spectrum of variation

14

Codominance

When alleles are equally strong and unmasked by others; multiple phenotypes expressed

red flower+white flower= pink flower

15

Number of autosomes in a human brain cell

44

16

Autosomal Dominant

If at least one chromosome has the allele the individual will be affected; any chromosome besides XY (AA or Aa)

17

Autosomal Recessive

Both chromosomes must have recessive allele for the individual to be affected; except XY chromosomes (Aa=carrier, aa= affected)

18

Sex (X) linked recessive

Trait only carried on the X chromosome; recessive allele must be on X chromosome for expression