TEST 2: Fertilisation and hereditary

Conception/ Fertilization

• Happens in the fallopian tubes

• When the sperm and ovum combine

• sperm is ejaculated, smells the egg, and heads towards it 

• only the strongest sperm make it to the egg

  • some are weak and die off and some are killed by the uterus 

• once fertilized, it triggers cell duplication 

• cells need to attach itself to the uterus wall 

  • if it doesn’t attach, it can cause complications in pregnancy 

Fraternal twins

When 2 sperm fertilize the egg

Zygote

Is the cell once it is fertilized

How many chromosomes do we get from each parent

23 cells from each parent

How many chromosomes do we have in our body?

46 chromosomes total

When does egg quality decline in woman?

Quality begins to decline around 30

• mitochondria and vibrancy in the cell weakens

Ovum

• The female egg

• Females are born with all the eggs they will ever have

• Once they start menstruating, An egg is released every 28 days until menopause

Sperm

• produced in the testicles

• Weakens later than woman (later 30s)

• Caffeine and tight clothes affect sperm health

Cillia

Tiny hairs in the fallopian tube that pushes ova to the uterus

Semen

Fluid from penis

Autosomes

• non sex chromosomes

• We have 22

What are some causes of infertility?

• Affects 15-20% of couples

• old age

  • By 35 and 40, its hard to have kids without assisted reproductive technology 

• hormones: some women start menopause sooner 

• Decreasing quality 

  • After 30, quality of ova decreases

• disease

  • Causes abnormal sperm shapes and blockages in the fallopian tube due to STIs or Pelvic infections

Assisted Reproductive technology (ART)

• conception through artificial means

• increases chance of birth defects

• IUI and IVF

Artificial Insemination (IUI)

• When sperm is injected into a woman’s vagina, cervix or uterus 

• Used if people have difficulties putting sperm to the egg 

• male gives a sperm sample and they implant it on the egg

In Vitro Fertilization (IVF)

• Woman receives fertility drugs to stimulate the production of multiple ova

• ova are then surgically removed and fertilized in a Petri dish

• Then implanted in a woman’s uterus 

  • To increase success, multiple embryos are implanted(risked multiple births) 

    • unused embryos may be frozen for later use 

    • some people donate them to research 

Ovum Transfer

• When a donor egg from a younger, fertile woman is fertilized (IVF style) and implanted into the mother’s uterus 

• Used if the mother's own ova is bad quality 

Surrogacy

• When a fertile woman is impregnated by the father through Artificial insemination  or IVF

• she carries the baby to term and then gives it to the parents 

Adoption and fostering

• hard to do in Canada because it takes forever 

• more likely to be Black, Asian, Indigenous or Alaskan Native kids 

• adopted families are MOST LIKELY to have a disability or special needs 

Deoxyribonucleic Acid (DNA)

• Genetic blueprint

• Has letters of genetic code that are read by the cells

• Double helix

  • Contains: Adenine, thymine, cytosine, guanine

Chromosome

• coils of DNA that consists of smaller segments (genes) found in every cell of the human body

Genes

The small segments of DNA (in our chromosomes) that instruct our bodies on what to do

• different segments instruct different things

• Some genes tell us our traits (hair colour, eye colour)

Genome

• Complete sequence of genes in the human body

• all of our genes

• Unique to each person

Sex chromosomes

• The 23rd pair of chromosomes

• Females have XX

• Males have XY

• Each parent gives one

  • Chromosome from the father determines sex (X or Y)

Epigenetics

• a field that shows how environmental influences affect the expression of genes 

• says that GENES AREN'T SET IN STONE 

  • ie. influence of smoking on a embryo and abuse

Mutation

When a gene is marker by cellular damage

Alleles

Genes that produce alternative expressions.

Multi factorial transmission

The combination of genetic and environmental factors to produce certain complex traits

Reaction range

The potential variability, depending on environment

Reactive correlation

• Different genetic makeup between parent and child

• Child’s characteristics prompt parents to adjust the environment for children’s growth

  • Noticing your kid is really musical (you are not) but you enrol them in classes

Active correlations

When the person’s select experiences are consistent with their tendencies

• person realizes they are good at reading, so they often go to the library

Passive correlation

When you Inherent from genes and environment

• your parents are musical, so you are genetically musical, but you are also surrounded by music because of your parents

Genotype

• the genetic code of an individual

• The Information in the cell/ having certain alleles

  • E.g. Gene segment reading A-T-G-C

Phenotypes

• The expression of the genotype that is visible and can be observed

  • I.e. colour of a person’s eyes, or musical skill (if individual has the genetic predisposition)

Klinefelter Syndrome

• only in males 

• extra x chromosomes (47 chromosomes, XXY) 

• taller

• enlarged breast 

• smaller testicles 

• impaired fertility

Turner Syndrome

• only in females 

• partial absence/ loss of X chromosome (45 chromosome, X)

• Shorter 

• Webbed neck 

• low-set ears

• infertility

Down syndrome

• comes from an extra 21st chromosome 

• downward-sloping skin fold at the inner corners of the eyes

• slowed growth

• thick hands 

• impaired communication 

• developmental delays 

• not contagious 

• many cases have been linked to alcohol use during pregnancy 

Heritability

• the statistical estimate of how much hereditary contributes in a specific trait at a certain time within a given population

  • What is the likelihood of you getting something based on your genes?

• Expressed from 0.0-1.0 — eye colour is 1.0

  • Includes: family studies, adoption studies, twin studies

Genetic counselling

clinical service that advised prospective parents of their probable risk of having children with hereditary defects