Ava Resendez- Chapter 3: Principles of Genetics

Who formed the foundational work of genetics?

Gregor Mendel

What did Mendel’s experiment show?

traits are not blended but are passed down as discrete units

What did Mendel’s P1 generation show? 

by crossing two true-breeding plants with different traits (like a purple-flowered plant and a white-flowered plant), the offspring (F1 generation) would only display one of the parental traits, which he called the "dominant" trait

What happened when Mendel crossed yellow and green peas? 

he observed the inheritance pattern in the F1 generation

What is Mendel’s Law of Segregation?

during the formation of gametes (sperm and egg cells), the two alleles for a specific trait separate, or "segregate," so that each gamete receives only one allele

What is a punnett square?

a chart used in genetics to determine the possible genotypes and probabilities of an offspring from a specific cross between two parents

How are punnett squares used in biotechnology?

to predict the outcomes of crosses in selective breeding and genetic engineering to determine the probability of offspring with specific traits

What is the Law of Independent Assortment? 

a principle of genetics stating that the alleles for different traits separate independently of one another during the formation of gametes

Why is the Law of Independent Assortment important in biotechnology?

it is fundamental to genetic analysis, prediction, and manipulation, particularly in breeding programs for desirable traits and understanding the creation of new genetic combinations

What is a testcross? 

a genetic cross where an individual with an unknown genotype (but a dominant phenotype) is crossed with an individual that is homozygous recessive for the trait of interest

What is homozygous?

having two identical alleles of a particular gene or genes.

What is heterozygous? 

having two different alleles of a particular gene or genes.

Why are test crosses important in biotechnology?

for determining an unknown genotype, which helps in breeding programs and genetic research by allowing the selection of individuals with desirable traits and confirming genotype-phenotype relationships

What is incomplete dominance? 

a genetic trait where one allele is not completely dominant over another, resulting in a blended, intermediate phenotype in the heterozygote

What does incomplete dominance show in biotechnology?

how intermediate phenotypes arise from combining genetic traits

What is codominance?

a genetic inheritance pattern where two different alleles for a gene are both fully and separately expressed in an individual, resulting in a phenotype that shows both traits

What is an example of a trait determined by codominance? 

human ABO blood type

Why is codominance important in biotechnology?

it allows for the development of organisms with enhanced or combined desirable traits through selective breeding

What is polygenic inheritance? 

a pattern where a single trait is influenced by the combined effects of multiple genes, resulting in a continuous range of phenotypes rather than distinct categories

What is a classic example of polygenic inheritance?

human height

What type of result does polygenic inheritance produce? 

a continuous range of phenotypes

How is sex determined?

primarily based on the presence or absence of the Y chromosome. 

Why is sex determination important in biotechnology? 

for applications like selective breeding of crops to improve yield, for sex-specific therapies, and for understanding sex-linked genetic diseases in both humans and animals

How are sex linked traits determined?

by genes located on the sex chromosomes, primarily the X chromosome because it is larger and contains more genes than the Y chromosome

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

because they only have one X chromosome

How do females express sex linked disorders?

Females typically do not express sex-linked disorders

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

diagnosing and managing genetic disorders, developing targeted therapies, and implementing gene editing strategies

What are chromosomal alterations?

changes in the number or structure of chromosomes, which can result in missing, extra, or rearranged genetic material

What is deletion?

the removal or obliteration of written or printed matter, especially by drawing a line through it.

What is inversion?

the action of inverting something or the state of being inverted.

What is translation? 

the process of converting text from a source language to a target language, aiming to preserve the original meaning, tone, and context

What is duplication?

the action or process of duplicating something.

What is crossing over?

the process where homologous chromosomes exchange genetic material, creating new combinations of genes

Why is crossing over important in science and biotechnology? 

it creates genetic diversity, ensures proper chromosome segregation during meiosis, and plays a role in DNA repair

When does crossing over occur?

prophase I of meiosis

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 an abnormal number of chromosomes, leading to offspring with conditions like trisomy (an extra chromosome, as in Down syndrome) or monosomy (a missing chromosome, as in Turner syndrome)

What diseases does nondisjunction help explain?

Down syndrome (trisomy 21), Turner syndrome (monosomy X), and Klinefelter syndrome (XXY)

What is down syndrome?

a genetic condition caused by the presence of an extra copy of chromosome 21

What is turner syndrome? 

a genetic disorder that affects females, typically caused by the absence or partial deletion of one X chromosome

What is Klinefelter syndrome?

a genetic disorder that affects males, caused by an extra X chromosome