Riya Kodukula Chapter 3: Principles of Genetics

Who formed the foundational work on genetics?

Gregor Mendel

What did Mendel’s experiment show?

traits are passed from one generation to the next

What did Mendel’s P1 generation show?

two pure pea plants- yellow only produced yellow, green only produced green

What is Mendel’s Law of Segregation?

traits separate during reproduction and recessive traits can reappear.

What happened when Mendel crossed yellow and green peas?

only yellow seeds were made

What is a punnett square?

tool to predict inheritance of genes

How are punnett squares used in biotechnology?

predicts inheritance of genes and genetic disorders

What is the Law of Independent Assortment?

understanding how traits and genetic disorders are inherited independently.

Why is the Law of Independent Assortment important in biotechnology?

the inheritance of one trait (shape) does not affect the other (color)

What is testcross?

demonstrate whether a trait is homozygous or heterozygous

What is homozygous?

Trait has the same two alleles (RR or rr)

What is heterozygous?

Trait has two different alleles (Rr)

Why are test crosses important in biotechnology?

important for identifying carriers of disease or genetic disorders

What is incomplete dominance?

no single allele is fully dominant

What does incomplete dominance show in biotechnology?

creates intermediate phenotypes

What is codominance?

two alleles have equal power

What is an example of a trait determined by codominance?

blood type

Why is codominance important in biotechnology?

medicine, transfusions, and paternity testing

What is polygenic inheritance?

controlled by many genes

What is a classic example of polygenic inheritance?

skin color, height, weight

What type of results does polygenic inheritance produce?

a range of phenotypes

How is sex determined?

combination of chromosomes

Why is sex determination important in biotechnology?

genetic disorders and prenatal testing

How are sex-linked traits determined?

chromosomes

Why are males more likely to express X-linked disorders?

have one x chromosome

How do females express sex linked disorders?

eggs

Why is it important to understand sex-linked inheritance in biotechnology?

predict disease

What are chromosomal alterations?

changes in chrosmomes

What is deletion?

deleted allele

What is inversion?

flipped allele

What is translocation?

moved allele

What is duplication?

duplicated allele

What is crossing over?

Crossing over is the exchange of genetic material between homologous chromosomes during meiosis. This process creates new combinations of genes, leading to greater genetic diversity in offspring. It occurs when homologous chromosomes, one from each parent, pair up and exchange segments of their DNA. 

Why is crossing over important in science and biotechnology?

Crossing over is important in science and biotechnology because it generates genetic diversity by exchanging genetic material between homologous chromosomes. This variation is fundamental for sexual reproduction, natural selection, and adaptation, and its manipulation in biotechnology allows for applications like creating new hybrids and understanding genetic diseases. 

When does crossing over occur?

Crossing over occurs during prophase I of meiosis. At this stage, homologous chromosomes pair up and exchange segments of their genetic material, creating new combinations of alleles that will be passed on to offspring. 

What is nondisjunction?

1. the failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

What is the result of nondisjunction?

gametes with abnormal number of chromosomes

What diseases does nondisjunction help explain?

Nondisjunction helps explain various genetic disorders caused by an abnormal number of chromosomes

What is Down’s syndrome?

Down syndrome is a genetic condition caused by the presence of an extra copy of chromosome 21. This is known as trisomy 21. 

What is Turner syndrome?

Turner syndrome occurs when a female fetus inherits only one X chromosome instead of the usual two

What is Klinefelter syndrome?

Extra X chromosome during fertilization.